JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD I Year B.Tech-SYLLABUS COMPUTER PROGRAMMING

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1 JAWAHARLAL NEHRU TECHNOLOGICAL UNIVERSITY HYDERABAD I Year B.Tech-SYLLABUS COMPUTER PROGRAMMING UNIT - I Introduction to Computers Computer Systems, Computing Environments, Computer Languages, Creating and running programs, Program Development. Introduction to the C Language Background, C Programs, Identifiers, Types, Variables, Constants, Input / Output, Operators(Arithmetic, relational, logical, bitwise etc.), Expressions, Precedence and Associativity, Expression Evaluation, Type conversions, StatementsSelection Statements(making decisions) if and switch statements, Repetition statements ( loops)while, for, do-while statements, Loop examples, other statements related to looping break, continue, goto, Simple C Program examples. UNIT - II Functions-Designing Structured Programs Functions, user defined functions, inter function communication, Standard functions, Scope, Storage classes-auto, register, static, extern, scope rules, type qualifiers, recursion- recursive functions, Limitations of recursion, example C programs, Preprocessor commands. Arrays Concepts, using arrays in C, inter function communication, array applications, two dimensional arrays, Multidimensional arrays, C program examples. UNIT - III Pointers Introduction (Basic Concepts), Pointers for inter function communication, pointers to pointers, compatibility, Pointer Applications-Arrays and Pointers, Pointer Arithmetic and arrays, Passing an array to a function, memory allocation functions, array of pointers, programming applications, pointers to void, pointers to functions. Strings Concepts, C Strings, String Input / Output functions, arrays of strings, string manipulation functions, string / data conversion, C program examples. UNIT - IV Enumerated, Structure,and Union Types The Type Definition(typedef), Enumerated types, Structures Declaration, initialization, accessing structures, operations on structures, Complex structures, structures and functions, Passing structures through pointers, self referential structures, unions, bit fields, C programming examples, command line arguments, Input and Output Concept of a file, streams, text files and binary files, Differences between text and binary files, State of a file, Opening and Closing files, file input / output functions (standard library input / output functions for files), file status functions (error handling),positioning functions, C program examples. UNIT V Searching and Sorting Sorting- selection sort, bubble sort, Searching-linear and binary search methods. Lists- Linear list singly linked list implementation, insertion, deletion and searching operations on linear list, Stacks- Push and Pop Operations, Queues- Enqueue and Dequeue operations. TEXT BOOKS: 1. Computer Science: A Structured Programming Approach Using C, B.A.Forouzan and R.F. Gilberg, ThirdEdition, Cengage Learning. 2. Programming in C. P. Dey and M Ghosh, Oxford University Press.

2 2 Unit-1 Introduction to Computers Computer Systems, Computing Environments, Computer Languages, Creating and running programs, Program Development. Introduction to the C Language Background, C Programs, Identifiers, Types, Variables, Constants, Input / Output, Operators(Arithmetic, relational, logical, bitwise etc.), Expressions, Precedence and Associativity, Expression Evaluation, Type conversions, Statements-Selection Statements(making decisions) if and switch statements, Repetition statements ( loops)-while, for, do-while statements, Loop examples, other statements related to looping break, continue, goto, Simple C Program examples. Introduction to Computer Systems: A Computer is an electronic device that takes data and instructions as an input from the user, processes data, and provides useful information known as output. A computer is a system made of two major components Hardware and Software. The computer hardware is the physical equipment. The software is the collection of programs (instructions) that allow the hardware to do its job. Following figure represents a Computer System. The computers can perform complex and repetitive calculations rapidly and accurately Store large amount of data and information for subsequent manipulations Provide information to the user in many different forms. Compare items and make decisions. These capabilities of computers have enabled us to use them for a variety of tasks. Applications areas where the computers are used : Data Processing(commercial use) Numerical Computing(Scientific use) Message Communication( ) Image Processing(animation and industrial use) etc.

3 3 Computer Hardware: The Hardware components of the computer system consists of five parts : Input Devices Central Processing Unit(CPU) Primary Storage Output Devices Auxiliary Storage Devices The computer will be of no use unless it is able to communicate with the outside world. Input/Output devices are required for users to communicate with the computer. Input Devices: The input devices are used to enter information to the computer system. Some of the examples of input devices are keyboard, Mouse, Scanner, Touch Screen, Joystick, Light Pen etc. An input device is used to provide data and control signals form the user to an computer. Output Device: Output devices are the devices through which the user gets information from the computer. Some of the examples of output devices are Monitor, LCD, Printer, Plotter, Speakers etc. If the output is shown on the monitor, we call it as a soft copy. If it is produced on a paper by the printer, we call it as a hard copy. Central Processing Unit (CPU): The central processing unit (CPU) is the main part of a computer system which is responsible for all arithmetic calculations, movement of data, and comparison among the data. It can be called as the brain of the computer. The central processing unit in micro computer is also called as microprocessor.

4 4 The CPU consists of three functional units Control unit (CU) Arithmetic Logic Unit (ALU) Registers The Control Unit stores the instruction set which specifies the operation to be performed by the computer. Control unit transfers the data and the instructions to the Arithmetic Logic unit. Simply, it is responsible for supervising the operation of the entire computer system. The Arithmetic Logic Unit performs arithmetical or Logical operation on the received data. The Register, is a high speed storage area within the CPU that stores the data to be processed by the CPU and also stores the processed data. The power and speed of the CPU depends on the number of registers and the size of each register. Primary Memory: The Primary storage, also known as Main Memory, is a place where the programs and data are stored temporarily during processing i.e., the main memory holds instructions and data when a program is executing. The data in primary storage are erased when we turn off a personal computer. There are two types of Main Memory devices namely, 1. Random Access Memory and 2. Read Only Memory. Random Access Memory: RAM is also called as Read-Write memory, i.e., both read and write operations can be done in RAM. It is a type of computer memory that can be accessed randomly, i.e. any byte of memory can be accessed without touching the preceding bytes. RAM is volatile in nature i.e., the information present in these types of memory devices is lost as soon as the power is turned off. Read Only Memory: ROM is a type of memory that normally can only be read, as opposed to RAM which can be both read and written. The contents of ROM cannot be changed. It is non-volatile in nature i.e., the information present in these types of memory devices is not lost as soon as the power is turned off.

5 5 ROM is most commonly used to store system-level programs that we want to have available to the PC all the times. For Example, BIOS (Basic Input Output System) programs are stored in ROM which are need at the time of system booting process. Cache Memory is a memory placed between CPU and main Memory. It is faster compared to the primary memory. Parts of the program or data that need to be accessed repeatedly are stored in Cache Memory. Auxiliary Storage: The Auxiliary storage, also known as secondary storage (or external storage), it is the place where the programs and data are stored permanently. When we turn off the computer, our programs and data remain in the secondary storage ready for next time we need them. Secondary memory devices include Magnetic disks (like hard drives and floppy disks) Optical disks (CDs and CDROMs) Magnetic tapes Computer Software Software is a set of programs or collection of programs that are necessary for the functioning of a computer to perform certain tasks. A Program is a set of instructions written to carry out a particular task, so that the computer can follow them.

6 6 Computer Software is divided into two broad categories : System Software and Application software. System Software System software consists of programs that manage the hardware resources of a computer and perform required information processing tasks. These programs are divided into three classes: operating system, system support software and system development software. The operating system provides services such as a user interface, file and database access. The primary purpose of this software is to keep the system operating in an efficient manner while allowing the users access to the system. In simple words Operating system is as software which interacts with the hardware resources of the computer directly. It also provides the interface between user and computer. System support software provides system utilities and other operating services. Examples of system utilities are sort programs and disk format programs. Operating services consists of programs that provide performance statistics and security monitors to protect the system and data. The last system software category, System development software, includes the language translators that convert programs into machine language for execution,debugging tools etc. Application software Application software is directly responsible for helping user in solving their problems. It is broken in to two classes: general-purpose software and application-specific software. General purpose software is purchased from a software developer and can be used for more than one application.

7 7 Examples of general purpose software include word processors, database management systems, and computer aided design systems. They are labeled general purpose because they can solve a variety of user computing problems. Application-specific software can be used only for its intended purpose. A general ledger system used by accountants and a material requirements planning system used by a manufacturing organization are examples of application-specific software. They can be used only for the task for which they were designed they cannot be used for other generalized tasks. Each layer represents the connection point user interacts with application software to do some work. The application software interacts with operating system, which is a part of system software directly interacts with the hardware. The user can directly interact with operating system whenever needed. Computing Environment: Computing Environment is the entire set of conditions under which one operates a computer. Simply it refers to a hardware platform and the operating system that is used in it. There are four different computing environments Personal Computing Environment Time-Sharing Environment Client/Server Environment Distributed Environment

8 8 Personal Computing Environment : In this environment, all of the computer hardware components are tied together in our personal computer (PC). In this situation, we have the whole computer for our self; we can do whatever we want. Time-Sharing Environment: Employees in large companies often work in what is known as a time-sharing environment. In the time-sharing environment, many users are connected to one or more computers. Also, in the time-sharing environment, the output devices and auxiliary storage devices are shared by all of the users. In the time-sharing environment, all computing must be done by the central computer. In other words, the central computer has many duties : It must control the shared resources It must manage the shared data and printing It must do the computing. All of this work tends to keep the computer busy. In fact, it is some times so busy that the user becomes frustrated by the computer s slow responses. Example for time-sharing environments is a college lab in which a minicomputer is shared by many students.

9 9 Client / Server Environment : A Client/Server computing Environment splits the computing function between a central computer and user s computers. The users are given personal computers or work stations so that some of the computation responsibility can be moved from the central computer and assigned to workstations. The user s personal computer called clients, which will communicate with the powerful central computer called server. Because the work is shared between user s computers (clients) and central computer (server), response time and monitor display are faster and the users are more productive. Distributed Computing Environment: A distributed computing environment, the computing complexity will be distributed among multiple servers and clients. The internet provides connectivity to different servers throughout the world. This environment is reliable and scalable.

10 10 Computer Language: The operations of a computer are controlled by a set of instructions called computer program. Instructions are written to tell the computer: What operation to be performed Where to locate the data How to present the data When to make decisions The communication between two parties, whether they are machines or human beings, always needs a common languages or terminology. The language used in the communication of computer instructions known as the programming language. The computer has its own language and any communication with computer must be in its language or translated into this language. To write a program for a computer, we must use a computer a language. Over years computer languages have evolved from machine languages to natural languages. Machine languages Symbolic languages 1940s 1950s High Level Languages 1960s Machine Language (Low Level Languages): As computers are made of two-state electronic devices they can understand only pulse and nopulse i.e., 1 or 0 conditions. Therefore all instructions and data should be written using binary codes 1 and 0. The binary code is called machine code or machine language. Machine language is usually referred to as the First Generation Language. Advantages of machine language: Computers do not understand English, Hindi or any other language. They respond only to machine language hence no need of any translator. The computer directly starts executing the machine language instructions and it takes less execution time. Disadvantages of machine language: Machine dependent: The computers are not identical in design; therefore, each computer has its own machine language.

11 11 Difficult to use and Error prone: It is difficult to understand and remember various combinations of 1 s and 0 s representing numerous data and instructions. This makes it difficult for a programmer to write error-free instructions. Difficult to debug and modify: checking error locations in machine instructions is as tedious as writing the instructions. Further, modifying such a program is highly problematic. Time consuming: Writing error-free instructions in machine language is a slow process. Assembly Language (Symbolic languages): The Assembly Language, introduced in 1950s, reduced program complexity and provided some standardization to build an application. It is considered as a Second-Generation Programming Language. Unlike machine level language here we use some codes known as mnemonic codes can be called as operation code or opcode. mov al,061h In the above instruction, the opcode move is used to move the hexadecimal value 61 into processor register al. In case of assembly language a translator is required to translate assembly language to machine langue. The translator program used in assembly language called as Assembler. Advantages of assembly language: Writing a program in assembly language is more convenient when compared to machine language. Instead of binary sequence, as in machine language, a program in assembly language is written in the form of symbolic instructions. This gives the assembly language program improved readability. Disadvantages of assembly language: Machine-dependent: Although symbolic languages greatly improved programming efficiency, they still require programmers to concentrate on the hardware that they are using. Programming is difficult and time consuming. High Level Language: Although symbolic languages greatly improved programming efficiency, they still require programmers to concentrate on the hardware that they are using. The desire to improve programmer efficiency and to change the focus from the computer to the problem being solved led to the development of high- level language, i.e., High- level languages are designed to relieve the programmer from the details of the assembly language.

12 12 High- level languages are to be converted into machine language. The process of converting them is known as Compilation and the tool used to convert is compiler. In this language, instructions are written using normal English language and mathematical symbols like +, -, %, / etc. Advantages of high level languages: Readability: Programs written in these languages are more readable than those written in assembly and machine languages. Ease in the development of programs: Since the instructions of these programming languages are closer to English language, it is easy to develop programs in high-level languages. Portability: High level programming languages can be run on different machines with little or no change. Easy debugging: Errors can be easily detected and removed. The following figure shows the simple English statement in high level language(c) and machine level language. High-level languages can be classified into 3 categories Procedure oriented languages (Third Generation Languages) Problem oriented language (Fourth Generation Languages) Natural language(fifth Generation Languages)

13 13 Procedure oriented languages (Third Generation Languages) : High level languages designed to solve general-purpose problems are called Procedural Languages or third generation languages. These include BASIC, COBOL, FORTRAN, C, C++ and JAVA which are designed to express the logic and procedure of a problem. The syntax of these programming languages is different and easy to follow. Another advantage of third generation languages is that they are portable i.e., we can put the compiler on any computer and create the object code. Problem oriented language (Fourth Generation Languages) : The problem - oriented languages are used to solve specific problems known as fourthgeneration languages. These include Query Languages. Report generators, and application generators which have simple English like syntax rules. Fourth-generation languages have reduced programming efforts and overall cost of software development. A single statement in a fourth generation language can perform the same task as multiple lines of a third generation language. Natural language (Fifth Generation Languages) : Natural languages are designed to make a computer to behave like an expert and solve problems; the programmer just needs to specify the problem. Natural languages such as LISP and PROLOG are mainly used to develop artificial intelligence and expert systems. Language Translators: A computer can understand only Each and every high-level language needs a translator to translate instructions written in the high-level programming language into a machine language that a computer can understand and execute. Different machines may need different compilers or interpreters for the same programming language. Assembler Compiler Interpreter Assembler: An Assembler is a computer program that takes each of the assembly language statement from the source code and translates them into machine language codes i.e., in the form of 0 s and 1 s. This output obtained in the binary format is called object or machine code. This code is finally executed to obtain the results.

14 14 Compiler: Compiler is a program that translates the source code written in a high level language into corresponding object code (i.e., executable machine code). This translation process is called compilation. A program that translates low level languages to high level language is called de-compiler. Interpreter: Interpreter is a type of program translator used for translating higher level language into machine language. It takes one statement of higher level languages, translate it into machine language and immediately execute it. Translation and execution are carried out for each statement. It differs from compiler, which translate the entire source program into machine code and does involve in its execution. The advantage of interpreter compared to compiler is its fast response to changes in source program. Interpreters are easy to write and do not require large memory in computer. The disadvantage of interpreter is that it is time consuming. Thus compiled machine language program runs much faster than an interpreted program. Creating and Running Programs: It is the job of a programmer to write and run the program. This process involves four steps. Writing and editing programs Compiling the program Linking the program with required library modules Executing the program Writing and editing programs: The software used to write programs is known as a text editor. A text editor helps us enter, change, and store character data. Depending on the editor on our system, we could use it to write letters, create reports, or write programs. Text editor is a generalized word processor, but it is more often a special editor included with the compiler. Some of the features of the editor are search commands to locate and replace statements, copy and paste commands to copy or move statements from one part of a program to another etc. After completing a program, we save our file to disk (with extension programname.c). This file will be input to the compiler; it is known as a source file.

15 15 Compiling the program: The source code file must be translated into machine language, which is the job of a compiler. The c compiler has actually two separate programs: 1. Preprocessor 2. Translator. The preprocessor reads the source code and prepares it for the translator. While preparing the code, it scans for special instructions known as preprocessor commands. These commands tell the preprocessor to look for special code libraries, make substitutions in the code, and in other ways prepare the code for translation into machine language. The result of the preprocessing is called the Translation Unit. After the preprocessor has prepared the code for compilation, the translator does the actual work of converting the program into machine language while converting translator checks correctness of each statement. If there are any syntactical errors the process of compilation ends here and those errors will be listed out by the Compiler. (In this step object code is created with the extension.obj.) An object module is the code in machine language called Object File (ProgramName.obj file) Even though the output of the compiler is machine language code, it is not yet ready to run; that is, it is not yet executable because it does not have the required C and other functions included. Linking the program Linking the program is essential process. It puts together all other program files and functions that are required by the program. For example, If the programmer is using sqrt() function, then the object code of this function should be brought from math.h library of the system and linked to the main() program. After linking, the file obtained is called "Executable File" (ProgramName.exe file). Executing the program The Executable file is loaded into memory for execution by a tool is called loader. Address at which program loaded is informed to CPU. Now CPU runs the program from the address given by loader.

16 16 Software or System Development Method: Today s large-scale, modern programming projects are built using a series of interrelates phases commonly referred to as the system development cycle. Although the exact number and names of the phases differ depending on the environment, there is general agreement as to the steps that must be followed. One very popular development life cycle is the Waterfall model. Depending on the company and the type of software being developed, this model consists of between five and seven phases.

17 17 The water fall model starts with system requirements. In this phase, all the requirements of a project will be gathered, the system analyst define the requirements. In the analysis phase, different alternatives will be analyzed from system's point of view. The design phase determines how the system will be built, the functions of individual programs and the design of files/database is completed. In the coding phase, the programs will be written. In the testing phase, all the programs will be tested together, to make sure that the system works as a whole. In the maintenance phase, the project will be put in work into production. Program Development: When we are given the assignment to develop a program, we will be given a program requirements statement and the design of any program interfaces. Also we should receive an overview of the complete project. Our job is to determine how to take the inputs we are given and convert them into the outputs that have been specified. This is known as program design. Program development is a multistep process which consists o the following steps: Understand the problem Develop a solution Write a program Test the program Understand the problem: The first step in solving a problem is to understand it carefully i.e., we need to have a clear idea about the problem. This can be done by asking the questing about the problem to the user. Develop a solution: Once we finally understand the problem, we use three tools in developing a solution. Structured Chart Algorithm/Pseudo Code Flow Chart A Structured Chart also known as a Hierarchy Chart is used to design the whole program, which shows the relationship of various units. (i.e., the functional flow the program). Algorithm is the Step by step procedure to solve a problem. Pseudocode is English- like statements that follow a loosely defined syntax and are used to convey the design of an algorithm. Pseudo code is part English, part program logic. Its purpose is to describe, in precise algorithmic detail, what the program being designed is to do. This requires defining the steps to accomplish the task in sufficient detail so that they can be converted into a computer program. Most of the statements in the pseudocode are easy to understand. Flowchart: Graphical representation of an algorithm is called as flowchart. A flowchart is a program design tool in which standard graphical symbols are used to represent the logical flow of data through function.

18 18 Writing a Program: After developing a solution the program has to be written in any programming language. Test the Program: After writing the program, it has to be tested to check if there are any errors or not. There are basically two kinds of testing techniques. a. Black Box Testing b. White Box Testing. Black Box Testing is done by the testing Engineer and the user. These people don t know what is there inside the program. They will just test the program using the given requirements set. White Box Testing done by the programmer who knows what is there inside the program and he can test each line of instruction in a program. Algorithm (Pseudo code): An Algorithm is the step-by-step process of solving a particular problem or algorithm is the step-by-step method of performing any task. Each step can be called as an instruction. Therefore, an algorithm is a finite set of well-defined instructions for accomplishing a specified task. There is a time and space complexity associated with each algorithm. Time complexity specifies the amount of time required by an algorithm and space complexity specifies the amount of space required. The algorithm that ensures best time and space trade off should be chosen for obtaining the desired solution. Features of an algorithm: Finiteness: An algorithm should terminate in a finite number of steps. Definiteness : Each of the algorithm must be precisely defined Effectiveness: All the operations used in the algorithm can be performed exactly in a fixed duration of time. Input: An algorithm has zero or more inputs Output: An algorithm has one or more outputs. Categories of an algorithm: Algorithms are divided into three categories: 1. Sequence 2. Selection 3. Iteration

19 19 Sequence: In this category all the instructions are performed one after the other. Selection: In the selection, instructions will be executed based on the condition, i.e., if the condition is true, some block of statements are executed; else if is false, another block of statements gets executed The selection form can be written as if(condition) then statement; if(condition) then statement1; else statement2; Iteration: In this category some of the instructions will be performed repeatedly for some specific number of times. Iteration statements are written using the following format. Repeat Statements; Until(Condition) The statements will be executed continuously if the condition is true. If the condition becomes false the next step will be executed. Pseudo Code: Pseudo code is a problem solving tool. It is quite similar to an algorithm but follows a loosely defined syntax. The goal of writing pseudo code is to provide high level description of an algorithm, which helps us to translate from an English language description of a problem to a program written in programming language like C. Ex : Write an algorithm for adding two numbers. Algorithm Step 1: start Step 2: read 2 numbers Step 3: add the 2 numbers Step 4: print sum Step 5: stop Pseudo code: Step 1: start Step 2: read 2 numbers a,b Step 3: sum <- a+b (or) sum = a+b Step 4: Display sum Step 5: stop We can write an Algorithm or Pseudo code for a given problem. In the above example the algorithm explains the process of solving the problem in simple English language where as the Pseudo code gives the programmatic representation of thsse problem. We can use any one of them or both.

20 20 Sequence, selection, iteration; all are same for Pseudo code and algorithm. Example Algorithms: Algorithm 1: To find the average of three numbers. Step 1: Start Step 2: Read the values a,b,c Step 3: average = (a+b+c)/3.0 Step 4: print average Step 5: stop Algorithm 2: To find the area and circumference of the circle. Step 1: start Step 2: read radius ( r ) of the circle Step 3: area 3.14*r*r Circumference *r Step 4: print the area, circumference Step 5: stop. Algorithm 3: To find the area of the triangle. Step 1: start Step 2: Read the value of a,b,c Step 3: Calculate three sides of the triangle using formula S (a+b+c)/2 Step 4: Find the area of a triangle apply formula area sqrt(s*s(s-a)*(s-b)*(s-c)) Step 5: print area Step 6: stop Algorithm 4: To swap given two numbers 10,20. Step 1: start Step 2: read a 10,b 20 Step 3: c a a b b c Step 4: print a, b Step 5: stop. Algorithm 5: To swap two variables without using another variable. Step 1: Start Step 2: read the values of a, b Step 3: 3.1 : a a + b 3.2 : b a b 3.3 : a a b Step 4: print a, b Step 5: stop.

21 21 Algorithm 6: To find the number is negative or positive. Step 1: start Step 2: Read n Step 3: if n>0 then Step 3.1 : print number is negative Step 3.2 : else print number is positive Step 3.3 : endif Step 4: stop Algorithm 7: To find greatest of two numbers. Step 1: start Step 2: Read a,b Step 3: if a>b then Step 3.1: print a is greater Step 3.2: else print b is greater Step 3.3: endif Step 4: stop. Algorithm 8: To find the roots of the quadratic equation. Step 1: start Step 2: Enter the value of a,b,c Step 3: discriminate (d) b*b-4*a*c Step 4: if d>=0 then Step 4.1: Root1 (-b+sqrt(d))/(2*a) Root2 (-b-sqrt(d))/(2*a) Step 4.2: print root1, root2 Step 5: if d <0 then Step 5.1: print roots are imaginary Step 6: stop. Algorithm 9: To find the largest of three numbers. Step 1: start Step 2: read a,b,c Step 3: if (a>b) and (a>c) then Step 3.1: print A is greater Step 3.2: else Step 3.2.1: if ( b > c ) then print B is greater Step 3.2.2: Else print C is greater Step 4: stop Algorithm 10: To find whether the given number is odd or even Step 1: Start Step 2: Read the number (n) Step 3: if(n%2===0) then Step 3.1: print even Step 3.2: Else print odd Step 4: stop

22 22 Flow chart: A Flow chart is a Graphical representation of an Algorithm or a portion of an Algorithm. Flow charts are drawn using certain special purpose symbols such as Rectangles, Diamonds, Ovals and small circles. These symbols are connected by arrows called flow lines. (or) The diagrammatic representation of way to solve the given problem is called a flow chart. The following are the most common symbols used in Drawing flowcharts: By using the basic flow chart symbols, we can design any program. Then we will combine them to design solutions to more complicated problems. There are three design structures, such as Sequence Selection and loop.

23 23 Sequence Structure: It is the simplest, because it is nothing more than a series of statements performed one after another. It is a sequence because the flow always continues in same direction every time the structure is executed. A sequence may include number of instructions, but each would be done in turn in the same order. Selection Structure: selection structure uses a decision to ask some question. This structure includes the decision and the operation to be performed in response to the decision. There will be two exists from the decision, but both of these branches are still a part of the selection structure, then both branches must rejoin a single flow line to exit the structure. Using these selection structure different steps may be executed depending on the result of the decision test. Sequence Structure Selection Structure Loop Structure : The loop structure are used to execute a sequence of steps in a number of times or until a particular condition is true. This structure will have a decision, one or more additonal symbols indicating the steps to be done within the loop, and a flow line that sends control back to the beginning of the loop. There are two loops are available Top Tested loop and Bottom Tested Loop Top Tested Loop: The top tested loops are leading decision loops means the decision is evaluated always at the first statement of the of the loop. If it is true, the control follows the flow lines that goes into the loop. If it is false, control follows the first statement after the loop. Bottom Tested Loop: The bottom tested loop is a trailing decision loop, means the decision is always evaluated at the last statement of the loop. The body of the loop will be executed once before control even gets to the loop test. If the condition is true then the control follows the flow lines that goes into the loop. If it is false, control follows the first statement after the loop.

24 24 Top Tested Loop Bottom Tested Loop Example Flowcharts: 1. Draw a flow chart for average of three numbers.

25 25 2. Draw a flow chart to find the roots of the quadratic equation. 3. Draw a flow chart to find the factorial of a given number.

26 26 Introduction to C Language: C is one of the most popular programming language, it was developed by Dennis Ritche at AT & T ( American Telephone & Telegraph) Bell Laboratories at USA in It is an upgraded version of two earlier languages, called BCPL and B, which were also developed at Bell Laboratories. The root map for all modern computer languages are started through the ALGOL language in early 1960 s after then COBOL( Common Business Oriented Language) was used for Commercial Application, FORTRAN was being developed for Scientific Application. At this stage, people started thinking about the single language which can program all possible applications. In 1967, Matrin Richards developed a language called BCPL (Basic Combined Programming Language) primarily for writing System Software. In 1970 Ken Thompson created a language using many features of BCPL and called it simply B. B was used to create early versions of UNIX at Bell Laboratories. C was evolved from ALGOL, BCPL and B by Dennis Ritche at Bell Laboratories in C used many concepts from these languages and added the concept of data types and other powerful features. The UNIX Operating System, which was developed at Bell Laboratories, was coded almost entirely in C. UNIX is one of the most popular operating system. Major parts of popular operating systems like Windows, UNIX, Linux is still written in C. Many other high-level languages have been developed based on C. For instance, Perl is a popular programming language in World Wide Web (WWW) design across the Internet. Perl actually borrows a lot of features from C. If you understand C, learning Perl is becomes easy. Another example is the C++ language, which is simply an expanded version of C, although C++ makes objectoriented programming easier. Also, learning Java becomes much easier if you already know C. During 1970s, C had evolved into what is now known as Traditional C. The language became more popular after publication of the book The C Programming Language by Brian Kernighan and Dennis Ritche in The book so popular that the language came to be known as K & R C among the programming community. The rapid growth of C led to the development of different versions of the language. To assure that the C language remains standard, in 1983, American National Standards Institute (ANSI) formed a technical committee to define a standard for C. the committee approved a version of C in 1989 which is now known as ANSI C. It was then approved by the international standard Organization in This version of C is also referred to as C89. During 1990 s, C++ a language entirely based on C, underwent a number of improvements and changes and became an ANSI/ISO approved language in November All popular computer languages are dynamic in nature. They continue to improve their power and scope by incorporating

27 27 new features and C is no exception. The Standardization Committee of C felt that a few features of that a new features of C++ / java, if added to c, would enhance usefulness of the language. The result was the 1999 standard for c. this version is usually referred as C99. The history and development of C is illustrated in figure. ALGOL International Group BCPL Martin Richards Ken Thompson Traditional C Dennis Ritche K&RC Kernighan & Ritche ANSI C ANSI Committee ANSI/ISO ISO Committee Standardization Committee B C99 Although C99 is an improved version, still many commonly available compilers do not support new features incorporated in C99. Features of C Language: C is general purpose, structured programming language. C is highly portable (i.e., it can be run in different operating systems environments). C is robust language whose rich set of built in functions and operators can be used to write any complex programs. C is well suited for writing system software as well as application software. C is a middle level language. it performs the task of low level language as well as high level language. We can write the codes for operating system, Application programs, Assembly language programs in C language. C has ability to extend itself. We can continuously add our own functions to the existing library functions. C programs are fast and efficient. This is due to its variety of data types and powerful operations. C language allows manipulation of data at the lowest level i.e., bit level manipulation. This features is extensively useful in writing system software program. C can be applied in systems programming areas like Compiler, Interpreters and Assemblers etc.

28 28 Structure of A C Program The program written in C language follows this basic structure. The sequence of sections should be as they are in the basic structure. A C program should have one or more sections but the sequence of sections is to be followed. 1. Documentation section 2. Linking section 3. Definition section 4. Global declaration section 5. Main function section Declaration section Executable section 6. Sub program or function section 1. Documentation Section : Documentation section comes first, it consist of set of comment lines giving name of the program, the name of the author and other details like flow of the program, describing or description about the functions, variables tec. The comment lines are nothing but same of kind of statements which are to be placed between the delimiters like /* & */. The complier ignores or doesn t compiles the comments. Thus we can say that comments are not a part of executable program The programmer can use frequently any number of comments that can be placed any where in the program. // this is a single comment line /* */ this is an example of multi comment lines 2. Link Section : The Link Section provides instruction to the compiler to link functions from the system library. In general the link section contains preprocessor directive statements. These statement starts with a pound sign(#). The preprocessor statements are used to include the header files to the current program. Each header file by default has an extension of.h. the header file should be included by using #include directive as given below. e.g. #include <stdio.h>

29 29 3. Definition Section : The Definition Section used to define all symbolic constants and assign them some value. e.g. #define MAX 25 Here #define is a compiler directive which tells the compiler whenever MAX is found in the program replace it with Global Declaration Section : This section declares some variables that are used through out the program (including main and other functions). These variables are known as Global variables. This section must be declared outside of all functions. Ex. int i; (before main()) 5. Main Function Section : Every program written in C language must contain the main() function. Empty parentheses after main are necessary. The main() function is the starting point of every C program. main() point from execution starts The execution of the program always begins with the main(). Except the main() section other sections may or may not necessary. The program execution starts from the opening brace and ends with closing brace. Between two braces the programmer should declare declaration and executable parts. Declaration part : The Declaration part declares all variables that are used in executable part. Initialization of variables can be done in this section. Executable part : The Executable part contains the statements followed the declaration of variables. This part contains set of statements or a single statement. These statements are enclosed between the braces. 6. Subprogram Section : The Sub Program section consist of all user defined functions that are called in the main function. User defined functions are generally placed immediately after the main function, although they appear in any order. SIMPLE C PROGRAM:

30 30 /* simple program in c */ #include<stdio.h> main() // starting point of the program printf( welcome to c programming ); /*printf() is a predefined function or built-in-function which is defined in stdio.h (standard input/output header file). It is used to print the data that is passed within double quotes on the console or output screen*/ /* End of main */ Explanation about Sample program: 1. The first line: /* sample C program */ is a comment. The comments in c used to describe about the program name, author other details etc. 2. The second line: #include<stdio.h> Any statement that starts with # symbol is known as preprocessor directives. The #include<stdio.h> informs or instructs the preprocessor to include the <stdio.h> header file to the current program. The header file consist of predefined or built-in functions. 3. The third line main() The main() is the starting point of the program. The program execution starts from main() function. The opening brace marks the beginning of the program closing brace indicates the end of the program. All the statements between the two braces form function body. The function body contains set of instructions to perform the given task. In the above program the function body contains only one state i.e., printf statements it is a predefined function for printing the output on the console or screen. Program Development steps: Editing phase Compiling phase Link phase Executing phase In case of Turboc IDE the following are shortcuts to invoke Compiler, linker ALT+F FOR COMPILING THE PROGRAM F FOR LINKING PROGRAM CTRL+F FOR EXECUTING THE PROGRAM ALT+F TO SEE THE OUTPUT Running C programs

31 31 The process of executing a C program is slightly different under Dos and UNIX. Running C programs in DOS : A C program must be converted into an executable file(i.e., a file with an.exe) to run it in DOS. First the c program has to be typed in a file using an editor. This file is called source file often, c compilers in many companies supplying C compilers for DOS. Some of the popular companies are Borland International, Microsoft Corp etc. Borland International itself has produced many C compilers such as TurboC, TurboC++ and Borland C++.(it must be mentioned at this part that c++ is superset of c and has the same syntax. A c program can be compiled by a c++ compiler.) In all these cases the actual compiler program into two forms : 1. As an IDE(Integrated Development Environment ) : 2. As a Command Line Compiler. As an IDE (Integrated Development Environment ) : The IDE includes all facilities to develop and run programs such as the editor, compiler, debugger and so on. In case of TurboC & TurboC++ the IDE is a program called tc.exe. In case of Borland C++ the IDE is invoked by typing a command bc or tc at the dos prompt. After installing TurboC or TurboC++ the following steps is to followed. Start my computer c drive tc or TURBOC click on Tc.exe

32 32 After typing the program, save the program with extension.c Now press ALT+F9 to compile the program. If the program contains any errors those errors are displayed to the programmer, no errors then object file is created with extension of.obj. Now we need press f9 then linker software is invoked. The linker combines different object files to produce the actual executable file. Now press ctrl+f9 to run the program, observe that screen will flicker for a moment, in reality the program has been executed by the IDE, it took a very short time to run, during which is printed on the screen and came back to the IDE. So how can we sure that the program has printed exactly what we wanted? For this we must view the output screen. By pressing ALT+F5 key we can see the message that has been printed on the screen after seeing the result of the program press any key to get back to the main IDE. As a Command Line Compiler This comes a program called tcc.exe in turboc & turboc++. The program is called bcc.exe in Borland C++. These are the programs that have to be invoked from the command line, and their purpose is to convert the c program into executable fle.\ For example, assuming that the file hello.c has been created using an editor, the command tcc hello.c type at the DOS prompt will convert the c programs hello.c to an executable program called hello.exe. In both of these case (IDE or Command line ) an executable file called hello.exe would have been generated. This program is standalone executable i.e., it can run independently without the help of any other file, the IDE or the compiler. Running a C program in UNIX Virtually every UNIX system has a C compiler called cc. on same UNIX systems a C compiler called gcc exits. Both are command line compilers. Their purpose is to convert the c program into executable code. The program has to be typed into a file separately using an editor such as vi etc. thereafter the command cc hello.c will create an executable file called a.out by default. This file can be executed by typing a.out at the prompt. C Basics

33 33 A programming language should be designed to support certain kind of data, such as numbers, characters, strings etc. to get useful output known as information. A program is a set of statements for a specific task, which will be executed in a sequential form. These statements/instructions are formed using certain words and symbols according to the rules known as syntax rules. Every program must follow accurately the syntax rules by the language. C Character Set The Characters used to form words, numbers and expressions depend upon the computer on which the program runs. The characters in C are classified in the following categories. 1. Letters 2. Digits 3. White spaces 4. Special characters Letters A...Z a z Digits 0 9 White Spaces Blank Space Horizontal tab Vertical tab New Line Form feed Special characters + plus, comma < lesser than - minus. full stop > greater than * asterisk ; semicolon = equal to / slash : colon ( open parenthesis

34 34 \ back slash apostrophe ) close parenthesis % percent double quote [ open bracket vertical bar & ampersand ] close bracket ~ tile # hash open set bracket close set bracket? question mark $ dollar! exclamation mark ^ caret _ underscore C-TOKENS: Tokens are individual words and punctuations marks in English language sentence. The smallest individual units are known as C tokens. Keywords: The C keywords are reserved words. All keywords have fixed meanings and these meaning cannot be changed. Keywords serves as basic building blocks for programs. All keywords must be written in lower case. The following are list of keywords. auto double int struct break else long switch case enum register Typedef char extern return union const float short unsigned

35 35 continue for signed void default goto sizeof volatile do if static while All keywords must written in lower case. Identifiers: Identifiers are names given to variables, functions and arrays etc. these are user defined names and consist of sequence of letters and digits with a letter as a first character. Both uppercase and lower case letters are permitted although lower case letters are commonly used. Rules for identifiers : 1. The First character of an identifier must be alphabetic character or under score. 2. The identifiers must contain only of alphabetic characters, digits or underscore 3. The identifiers cannot be a keyword 4. No space and special symbols are allowed. The underscore is used to link the two words in long identifiers or it is used to separate two different words. We can also define identifiers in definition section as follows. #define N 10 #define a 15 Here N & a are user defined identifiers. DATA TYPES : To represent different types of data in C program we need different data types. A data type is essential to identify the storage representation and the type of operations that can be performed on that data. C supports four different classes of data types namely

36 Basic Data types(primary or fundamental data types) Derives data types User defined data types Empty data types Basic Data types(primary or fundamental data types) : All C compilers supports the five fundamental data types called int, char, float, double. A Data is represented using numbers or characters. The numbers may be integers or real numbers. A Datatype is used to indicate the type of value stored in a variable. The data type of a variable is specified at the time of declaration and is attached till the end of a program. Various data types and its terminology used to describe them are given following figure. Size and range of Basic data types INTEGER TYPE: The integer data type is used to store the whole numbers. The integers does n t contain the

37 37 decimal point. They take the binary form for storage. On a 16-bit machine the range of integer values is to Signed integers Signed integers are those integers which uses 15 bits for storing the magnitude of a number and 1 bit to store the sign. The left most bit i.e., 16th bit is used for storing the sign, it is 1 for a negative number and 0 for the positive number. Unsigned integers Unsigned integer use all 16 i.e., (15+1) bits to store the magnitude i.e.,these are the whole numbers that always hold positive values and the sign bit(left most bit) also contains the value. (signed integers include sign whereas unsigned integers doesn t include sign). Size and range of Data types on a 16 bit machine

38 38 CHARACTER TYPE Characters are generally stored in 8 bits of the internal storage and a single character can be defined as char data type. Each character has an equivalent ASCII value i.e., these characters are internally stored as integers. Data Type Size (bytes) Range Control string format specifier char or signed char to 127 %c unsigned char 1 0 to 255 %c or FLOATING POINT TYPES Floating point (or real ) numbers are stored in 32 bits with the 6 digits of precision. These numbers are defined by using the keywords float and double, whereas the double data type uses the 64bits with the 14 digits of precision. Data Type Size (bytes) Range Control string or format specifier float 4 3.4E-38 to 3.4E+38 %f or %g double 8 1.7E-308 to 1.7E+308 %lf long double E E+4932 %lf to 2. DERIVED DATA TYPES: Derived datatypes are used in C to store a set of data values. Arrays and Structures are examples for derived data types.

39 39 Ex: int a[10]; Char name[20]; 3. USER DEFINED DATATYPES: C Provides a facility called typedef for creating new data type names defined by the user. For Example,the declaration, typedef int Integer; makes the name Integer a synonym of int.now the type Integer can be used in declarations,casts,etc,like, Integer num1,num2; Which will be treated by the C compiler as the declaration of num1,num2as int variables. typedef ia more useful with structures and pointers. Variable: A variable is an identifier that is used to store some specified type of value. The variable may take different values at different times during the execution. i.e., it is the named memory location. Rules for naming the variables : The first character of a variable must be an alphabet or an underscore(_) The length of the variable cannot exceed upto 8 characters long, and some of the C compilers can be recognized upto 31 character long. No commas or blank spaces are allowed within a variable name. The name of the must be chosen by the programmer in such a way that it should reflect the functionality of the variable. Variable Declaration: After designing suitable variable names, we must declare the variables in declaration part and this declaration tells the compiler what the variable name and type of the data that the variable will hold. Syntax Data_type v1,v2,v3 vn; Data_type is the type of the data v1,v2,v3,..vn are the list of variables

40 40 Ex : int n1, n2; Here the variables, code is integer type variables holds only integer values and price is float type variable holds fractional values int code; float price; Initializing Variables: Initialization of variables can be done using assignment operator ( = ). The variables can be initialized while declaration itself. Syntax : Variable_name = constant; Or Data_type variable_name = constant; Example 1: int i; float b; char c; //i, b are integer and float type of variables i=10; b=32.22; c= s ; Example 2 int i1=100; float b1=12.22; char a= k ; int a=b=122; a, b are initialized with 122. printf() : printf() is a predefined or built functions in C. which is used to print message and variables on the output screen. Syntax : printf( message ); printf( control string, var1,var2,var3..varn); printf( \n wel come to C programming ); // prints the data on the screen. printf( %d,a); // prints value of a

41 41 scanf() : scanf() is a predefined or built function in C, which is used to read information or values from the keyboard. Syntax : scanf( control string,&var1,&var2,.&varn); Ex : int a; scanf( %d,&a); // accepts the value of a from keyboard. /* write a program to assign a values to the variables */ #include<stdio.h> #include<conio.h> main() int a,b; float ff=32.7; printf( \n Enter any numbers ); scanf( %d%d,&a,&b); printf( \n User Entered Values : %d %d,a,b); printf( \n float value ff: %f,f); /* write a program to accept two numbers and add two numbers */ #include<stdio.h> #include<conio.h> main() int num1,num2,sum; printf( \n Enter any two numbers ); scanf( %d%d,&a,&b); sum=a+b; printf( \n sum of two numbers : %d,sum); Constants : Constants are data values that cannot be changed during the execution of a program. In C constants can be classified as follows.

42 42 Numeric Constants: Integer Constants: These are the sequence of numbers from 0 to 9 without decimal points or fractional part or any other symbols. There are three types of integer constants which forms different number system. Decimal Number : Decimal integers consists of set of digits 0 through 9, preceded by an optional ve or +ve sign. Valid example of decimal integer constants are Ex : Octal Number: Octal integer consists of any combination of digits from the set 0 through 7, with leading 0. Some of the examples of octal integer are Ex : Hexadecimal Number : Hexadecimal integers are sequence of digits preceded by 0x or 0X. They may also include alphabets A through F.( A=10, B=11, C=12, D=13, E=14, F=15). Following are the examples of hex integers Ex : 0X2 0x5F The largest integer value that can be stored is machine dependent. It is on 16-bit machines and 2,1247,483,647 on 32-bit machines. Real Constants : Integers numbers are inadequate to represent quantities that vary continuously, such as distances, heights, temperatures, prices and so on. These quantities are represented by numbers containing fractional parts like such numbers are called real or floating point constants. A real number may also be expressed in exponential ( or scientific) notation. For example the value may written as e2 in exponential notation. e2 means multiply by 10 ^ 2. The general form is : mantissa e exponent

43 43 The Mantissa is either a real number expressed in decimal notation or an integer. The exponent is an integer number with an optional plus or minus sign. Ex : 0.65e4 12e E3 Single Character Constants A single character constant contains a single character enclosed within a pair of single quote marks. It may be an alphabet, digit, white space or special character. We can t write more than one character in single quotes. Ex: a A 9 ^ Character are internally represented by integers ASCII.( American Standard Code for Information Interchange) Ex: a 97 A etc. There are 256 ASCII values. String Constant A String constant is a sequence of characters enclosed in double quotes. The characters may be letters, numbers, special characters and blank space. Ex : hello!, 123#7, skr27 Remember that a character contant (e.g., x ) is not equivalent to the single character string constant(e.g., x ). further a single character string constant does not have an equivalent integer value while a character constant has an integer value. BACKSLASH CONSTANTS The backslash constants are predefined which are to be used in o/p functions. \n new line \t horizontal tab \v vertical tab \a audible alert ( bell ) \r carriage return \b back space \f form feed \ single quote \ double quote \? Question mark \\ back slash \0 null Operators:

44 44 An operator is a symbol that tells the compiler to perform certain mathematical or logical manipulations. They form expressions. C operators can be classified as 1. Arithmetic operators 2. Relational operators 3. Logical operators 4. Assignment operators 5. Increment or Decrement op+erators 6. Conditional operator 7. Bit wise operators 8. Special operators 1. Arithmetic Operators : All basic arithmetic operators are present in C. Operator Meaning Examples + Addition 2+9=11 - Subtraction 9-2=7 * Multiplication 2*9=18 / Division 9/3=3 % Modulo division(remainder) 9%2=1 All the above operators are binary operators as they act upon two operands.

45 45 The modulo division gives the remainder of an integer division. An arithmetic operation involving only real operands(or integer operands) is called real arithmetic(or integer arithmetic). If a combination of arithmetic and real is called mixed mode arithmetic. Operation Result Example int / int int 2/5=0 real / int real 5.0/2=2.5 int / real real 5/2.0=2.5 real / real real 5.0/2.0=2.5 /*Ex 1: program to illustrate the usage of arithmetic operator.*/ #include<stdio.h> #include<conio.h> void main() int i,j,k; // integer variables clrscr(); // used to clear the screen i=10; j=20; k=i+j; printf("\n value of k : %d",k); getch(); Output :

46 46 /* program to find out all arithmetic operations on two given values */ #include<stdio.h> #include<conio.h> main() int a,b,c,d; int sum,sub,mul,rem; float div; clrscr(); printf("\n Enter the values of a,b :"); scanf("%d%d",&a,&b); sum=a+b; sub=a-b; mul=a*b; div=a/b; rem=a%b; printf("\n sum = %d, sub = %d, mul = %d, div = %f rem = %d",sum,sub,mul,div,rem); getch(); Output: 2. Relational Operators : We often compare two quantities and depending on their relation take certain decisions for that comparison we use relational operators. For example we my compare the age or salaries of two persons or the price of two items and so on. Operator Meaning Examples Result < Is less than 2<9 1 > Is greater than 1>2 0

47 47 <= Is less than or equal to 2<=2 1 >= Is greater than or equal to 3<=7 1!= Is not equal to 1!=1 0 == Is equal to 2==2 1 It is the form of AE1 relational operator AE2 AE1 & AE2 are constants or an expressions. When arithmetic expression are used on either side of a relation operator, the arithmetic expression will be evaluated first and then the result compared. /* program to use various relation operator*/ #include<stdio.h> #include<conio.h> void main() clrscr(); printf("\n Condition\t:\tResult "); printf("\n 5>5 \t:\t%d",5>5); printf("\n 10<100 \t:\t%d",10<100); printf("\n 100!=100 \t:\t%d",100!=100); printf("\n 100==100 \t:\t%d",100==100); getch(); Output : In above program the true condition returns 1 and false returns 0. In this example first and third conditions are false and second and fourth conditions are true. /* program to accept two numbers and find out which one is greater */ #include<stdio.h> #include<conio.h> void main() int num1,num2; clrscr(); printf("\n Enter any two integer numbers ");

48 48 scanf("%d%d",&num1,&num2); if(num1>num2) printf("\n %d is greater ",num1); else printf("\n %d is greater ",num2); getch(); Output: 3. Logical Operators : Logical operators are used to combine the results of two or more conditions or expressions. C has the following logical operators. && logical AND logical OR! logical NOT The logical AND (&&) operator is usually used in situation, where a set of statements are to be executed, if two or more expressions are true. The logical OR ( ) operator is used in situation, if either of them ( at least ) one condition must be true form two or more conditions or expressions. Then the set of statements are executed. The logical NOT (!) operator reverse the value of the expression it operates on. i.e., if makes a true expression false and false expression true. Op-1 Op-2 Op-1&&Op-2 Op-1 Op-2 Non-Zero Non-Zero 1 1 Non-Zero Non-Zero 0 1

49 0 Non-Zero Op-1!Op-1 Non-Zero Example : i is an integer variable with value of 7 f is float variable with value of 5.5 c is a character variable which represents w character. The following expressions (i>=6)&&(c== w ) returns true i.e., 1 (f<11)&&(i>100) returns false i.e., 0 (c!= p ) (i<=100) returns true i.e., 1 // program to illustrate relational operator #include<stdio.h> #include<conio.h> void main() int c1,c2,c3; clrscr(); printf("\n enter the values of c1, c2 and c3 "); scanf("%d%d%d",&c1,&c2,&c3); printf("\n condition : return values(1---true,0---false) "); printf("\n c1>c2 : %d ", c1>c2); printf("\n c2<=c3 : %d ", c2<=c3); printf("\n c3!=c1 : %d ", c3!=c1); getch();

50 50 Output : /* program to print logic 1 if input character is capital otherwise 0 */ #include<stdio.h> #include<conio.h> main() char x; int y; clrscr(); printf("\n enter a character "); scanf("%c",&x); y=(x>=65 && x<=90); printf(" y : %d ",y); getch(); /* In the above program a character is entered. using logical operator and entered characters ascii value is checked. if it is in between 65 and 90 the result displayed will be 1 otherwise 0.the and operator joins two conditions. if the condition is true 1 is assigned to y otherwise 0.*/ Output :

51 51 /* write a program to display 1 if inputed number is either 1 or 100 otherwise 0. Use logical or operator*/ #include<stdio.h> #include<conio.h> main() int num,res; clrscr(); printf("\n enter any number "); scanf("%d",&num); res=(num==1 num==100); printf("\n res : %d ",res); getch(); /*In the above program the or operator checks two conditions. if one of the conditions satisfies 1 is assigned to res otherwise 0.*/ Output : /* write a program to display 1 if inputted number is between 1 to 100 otherwise 0. Use logical && operator*/ #include<stdio.h> #include<conio.h> main() int num,res; clrscr(); printf("\n enter any number "); scanf("%d",&num); res=(num>=1 && num<=100); printf("\n res : %d ",res); getch(); /* In the above program the and operator checks two conditions. if both condtions are conditions satisfies 1 is assigned to res otherwise 0.*/ output :

52 52 5. Assignment Operators : They are used to assign the result of an expression to a variable. The assignment operator is '='. Syntax : variable_name = expression or value; X = 10; // x is variable x=x+1; or x+=1; C provides compound assignment or short hand assignment operators are used to assign a new value to a variable after performing a specified operation. Ex : x+=y; is same as x=x+y; Operator Statement with simple assignment operator += x+=y x=x+y x-=y x=x y x*=y x = x*y /= x/=y x = x/y %= x%=y x=x%y - = * = Statement with shorthand operator 6. Increment and Decrement operators : C has two vey useful operators, they are increment (++) and decrement (--) operators. The operator ++ adds 1 to the variable or operand, while subtracts 1 from the variable or operand. Both are unary operators. Because they act upon only one variable. ++x Pre Increment or prefix increment operator x Post Increment or postfix increment operator --x Pre decrement or prefix decrement operator x Post decrement or postfix decrement operator A prefix increment operator first adds 1 to the operand or variable and then the result s assigned to the variable on the left. On the other hand, a postfix increment operator first assigns the value to the variable on left and then increments the operand.

53 53 Similar is the case when we use decrement (--) operator. /* program to demonstrate increment and decrement operators */ #include<stdio.h> #include<conio.h> main() int a=3,b=5; clrscr(); printf("\n a = %d, b = %d ",a,b); printf("\n "); printf("\n post increment operation "); printf("\n "); printf("\n a++ = %d, b++ = %d",a++,b++); printf("\n a = %d, b = %d ",a,b); printf("\n "); printf("\n pre increment operation "); printf("\n "); printf("\n ++a = %d, ++b = %d ",++a,++b); printf("\n a = %d, b = %d ",a,b); printf("\n "); printf("\n post decrement operation "); printf("\n "); printf("\n a-- = %d, b-- = %d ",a--,b--); printf("\n a = %d, b = %d ",a,b); printf("\n "); printf("\n pre decrement operation "); printf("\n "); printf("\n --a = %d, --b = %d ",--a,--b); printf("\n a = %d, b = %d ",a,b); getch(); /* where a++ post increment, first do the operation and then increment ++a pre increment, first increment and then do the operation a-- post decrement, first do the operation and then decrement --a pre decrement, first do the operation and then decrement */

54 54 Output : 7. Conditional Operator : A ternary operator pair "? :" is available in C to construct conditional expressions of the form exp1 or condition? exp2 : exp3; It work as if exp1 or condition is true then exp2 else exp3 the? : operator acts as a ternary operator, it first evaluate the condition, if it is true (non- zero) then exp1 is evaluated, if the condition is false (zero) then the exp2 is evaluated. /* program to find greatest of two numbers by using ternary operator*/ #include<stdio.h> #include<conio.h> main() int n1,n2; clrscr(); printf("\n Enter the values of n1, n2 :"); scanf("%d%d",&n1,&n2); printf(n1>n2?"\n n1 is greater ": "\n n2 is greater "); getch(); Output :

55 55 8. Bit wise Operators : C supports special operators known as bit wise operators for manipulation of data at bit level i.e., these operations on the bits of a binary format of an integer. They are not applied to float or double. Operator Meaning & Bitwise AND Bitwise OR ^ Bitwise exclusive OR << left shift >> right shift ~ one's complement 9. Special Operators : These operators which do not fit in any of the above classification are,(comma), sizeof, Pointer operators(& and *) and member selection operators (. and ->). The comma (,) operator is used to link related expressions together. The operations are performed from left to right and the result obtained at last operation is assigned to a variable. Ex: int i=0,j; j=(i+=2,++i,i*3); Here first i+=2 is performed (result is i=2) then ++i (result is i=3 and at last i*3 is performed (result is i=9) and the resultant value is stored in j. j=9

56 56 /* program to swap two integer variables using the commo operator #include<stdio.h> #include<conio.h> main() int n1,n2,n3; clrscr(); printf( \nenter two integers : ); scanf( %d%d,&n1,&n2); printf( \n-----before Swaping-----\n ); printf( n1 = %d\tn2 =%d,n1,n2); n3=n1,n1=n2,n2=n3; printf( \n-----after Swaping-----\n ); printf( n1 = %d\tn2 =%d,n1,n2); getch(); in looping statements. (for,while) Tthe sizeof operator is used to know the size of an operand. Syntax : sizeof(operand) The & operator prints address of the variable in the memory. Syntax : &(variable) /* program to use & and sizeof operator and determine the size of integer and float variables*/ #include<stdio.h> #include<conio.h> main() int x=2; char c='a'; float y=2; clrscr(); printf("\n sizeof(x) = %d bytes",sizeof(x)); printf("\n sizeof(c) = %d bytes",sizeof(c)); printf("\n sizeof(y) = %d bytes",sizeof(y)); printf("\n address of x = %u bytes and y = %u",&x,&y); getch();

57 57 Type Casting: Type Casting or Type conversion refers to the process of conversion of one data type to another data type. There are two types of type conversions i. ii. Implicit type casting Explicit type casting. Implicit type casting It is an automatic type casting. Ex: int a = 9.5; here system truncates the decimal part of 9.5 and assigns only integral part to integer variable (TRUNCATION) float x=10; here system promotes value 10 to 10.0 (PROMOTION). char ch=65; here integer value 65 is converted into A. Explicit type casting It is process of converting one data type to another forcefully. It is to be done by the programmer or user. The general form of explicit type cast is (type name) expression type name is one of the standard C data types whereas expression may be a constant, variable or an expression. Ex: float a=9.6; float b=3.2; int c = (int)a%(int)b; Now modulo division is performed in integer mode

58 58 Expression An Expression is a sequence of operands and operators that reduces to a single value. Expression can be simple or complex. A Simple Expression contains only one operator. (Ex : 2+3) A Complex Expression contains more than one operator. Ex : 2+5*2 To evaluate a complex expression, we reduce it to a series of simple expressions. In the previous example we first evaluate the simple expression 5*7 and then the expression giving result of 37. Precedence is used to determine the order in which the different operators in a complex expression are evaluated. Associativity is used to determine the order in which operators with the same precedence are evaluated in a complex expression. Precedence is applied before associativity the order in which expressions are evaluated. Associativity is then applied, if necessary. Each operator in C has a precedence associated with it. This precedence is used to decide how to solve an expression involving more than one operator. Generally operators at higher levels of precedence are evaluated first. The operators of the same precedence are evaluated either from left to right or from right to left depending on the level. This is known as associativity rule The following table gives you a complete list of operators, their precedence levels, and their rules of association. Rank 1 indicates highest rank and 15 the lowest. Operator Description () Parentheses [] Brackets(array subscript). and -> Member selection operators ++ Post increment -- Post decrement Associativity Precedence Level Left to-right 1

59 59 + Unary plus - Unary minus ++ Pre increment -- Pre decrement! Logical Not ~ One s complement (type) Type cast conversion & and * Pointer operators Sizeof Determine size in bytes * Multiplication / Division % Modules + Addition - Subtraction << Bitwise left shift >> Bitwise right shift < Less than <= Less than or equal to > Greater than >= Greater than or equal to == Equal to!= Not equal to Right-to-left 2 Left-to-right 3 Left-to-right 4 Left-to-right 5 Left-to-right 6 Left-to-right 7

60 60 & Bitwise AND Left-to-right 8 ^ Bitwise XOR Left-to-right 9 Bitwise OR Left-to-right 10 && Logical AND Left-to-right 11 Logical OR Left-to-right 12?: Ternary Right-to-left 13 Assignment Operators Right-to-left 14 Comma Left-to-right 15 = += -= *= /= %= &= ^= = <<= >>=, Associativity: Associativity can be left-to-right or right-to-left. Left to-right associativity evaluates the expression by starting on the left and moving to the right. Conversely, right-to-left associativity evaluates the expression by proceeding from the right to the left. Associativity is applied when we have more than one operator of the same precedence level in an expression.

61 61 Left-to-right Associativity: The following shows an example of left-to-right associativity. Here we have four operators of the same precedence (* / % ). 3*8/4%4*5 Associativity determines how the subexpressions are grouped together. All of these operators have the same precedence(3). Their associativity is form left to right. So they are grouped as follows: (((3*8)/4)%4)*5) The value of this expression is 10. Right to left associativity : Several operators have right-to-left associativity as shown in the precedence table. For example, when more than one assignment operator occurs in an assignment expression, the assignment operators must be interpreted form right-to-left. This means that rightmost expression will be evaluated first then its value will be assigned to the operand on the left of the assignment operator and the next expression will be evaluated. a+=b*=c-=5 is evaluated as (a + = (b*=(c-=5))) Which is expanded as (a=a+(b=b*(c=c-5))) If a has an initial value of 3, b has an initial value of 5, and c has an initial value of 8,these expressions become (a=3+(b=(5*(c=8-5))) Which results in c being assigned a value of 3, b being assigned a value of 15, and a being assigned a value of 18. The value of the complete expression is also 18. Evaluation of Expression:

62 62 While evaluating an expression the operator with highest precedence will be evaluated first, then the second highest precedence operator and the operator with least precedence will be evaluated last. * / % have higher priority level (3) + - have lower priority level(4) Let us consider the following expression a%3-b/2+(c*d-5)/e Where a=30,b=10,c=11,d=5,e=10 Replacing the values of a, b, c,d, e in the expression we get Step 1 30%3-10/2+(55-5)/10 Step 2 30%3-10/2 + 50/10 (operation with in parentheses) Step /2+50/10 ( here we are following left to right associativity,% operation ) Step /10 ( / operation ) Step ( - operation ) Step 6 0 (+ operation ) /* program to demonstrate operator precedence */ #include<stdio.h> #include<conio.h> main() int a=30,b=20,c=10; clrscr(); printf(" \n a*b+c : %d", a*b+c); // 610 printf(" \n a*(b+c) : %d", a*(b+c)); // 900 printf(" \n a+b*c : %d", a+b*c); //230 printf(" \n a-b/c : %d", a-b/c); //28 printf(" \n --a+b*c : %d", --a+b*c); //29+200=229 printf(" \n a-b++/(c-3) : %d",a-b++/(c-3)); //27 getch(); Output :

63 63 Input / Output We know that input, process, output are the three essential features of computer program. The program takes some input data, processes it and gives the output. we have two methods for providing data to the program. Assigning the data to the variables in a program By using the input/output statements. In C language two types of Input/Output statements are available, and all input and output operations are carried out through function calls. Several functions are available for input/output operations in C. These functions are collectively known as the standard I/O library. i. ii. Unformatted Input / Output Statements Formatted Input/ Output Statements

64 64 Unformatted Input / Output Statements These statements are used to Input or Output a single/group of characters. Or these statements or functions are used to accept/display the single or group of characters from/to the user. getchar() : getchar() is used to read a single character from the input device(keyboard). varname=getchar(); the getchar() function is defined in standard I/O library. Syntax : char variable_name = getchar(); Char : datatype Variable_name any valid c variable. Ex : char x; X=getchar(); #include<stdio.h> #include<conio.h> #include<ctype.h> main() char ch; printf("\n Enter any character..."); ch=getchar(); if(isalpha(ch)>0) printf("\n It is a alphabet "); else if(isdigit(ch)>0) printf("\n It is a digit "); else printf("\n It is alphanumeric "); getch(); /* isalpha() is predefined function from ctype.h file. It is used to check whether the character variable consists of alphabet or not. If it consist of alphabet it returns 1 otherwise 0. */ Output :

65 65 putchar() : The putchar() function is used to display one character at a time on the standard output device. Syntax : putchar(character_variable); Ex : char ch= a ; putchar(ch); /* program to convert a character from lower to uppercase */ #include<stdio.h> #include<conio.h> main() char ch; clrscr(); printf("\n Enter any Alphabet in lower case \n..."); ch=getchar(); ch=ch-32; putchar(ch); getch(); /* a to z is 97 to 122 A to Z is 65 to 90 0 to 9 is 48 to 57 back space is 8 enter key is 13 space bar is 32 */ output : getc() : the getc() is used to accept a single character from the standard input to a character variable. Syntax : char ch=getc(); putc() : the putc() is used to display a single character on the standard output device. char ch= y ; putc(ch);

66 66 gets() : the gets() function is used to read the string from the standard input device(keyboard). Syntax : gets(character type of array variable name); puts() : the puts() function is used to display the string to the standard output devive(monitor). puts(character type of array variable name); getch() and getche() functions : The getch() read a single character directly from the keyboard, without echoing to the screen. The getche() reads a single character form the keyboard and echoes it to the screen. /* program to demonstrate the getch() and getche() functions */ #include<stdio.h> #include<conio.h> main() char c,ch; clrscr(); printf("\n Enter any character "); c=getch(); printf("\n Enter another character "); ch=getche(); printf("\n first entered character : %c ",c); printf("\n second entered character : %c",ch); getch(); Output :

67 67 Formatted Input/Output Statements : Formatted input/output refers to input and output, that has been arranged in a particular format. The following are the input and output functions scanf() and printf() we have already used this input function in number of examples. the scanf() functions is used to read data from the standard input device i.e, keyboard. Scanf() : The scanf() statement or function reads all types of data values. It is used for runtime assignment of variables. The scanf() statement also requires conversion symbol to identify the data to be read during the execution of a program. Syntax : scanf( control string,&var1,&var2, &varn); The scanf() function requires & operator called address operator. The role of address operator in scanf() function is to indicate the memory location of the variable, so that the value read would be placed at that location. The scanf() function also returns values. The return value is exactly equal to the number of values correctly read. The below table illustrates control string in Input / output statements : Format specifier Meaning %c Single character %d Decimal integer upto 32,768 ti 32,767 %s String %f Float values %ld Long integer upto -65,536 to 65,535 %u Unsigned decimal %o Octal number %x Hexa decimal number

68 68 Floating point value %e /* program to find the average of three numbers */ #include<stdio.h> #include<conio.h> main() int n1,n2,n3,sum; float avg; clrscr(); printf("\n Enter any Three integers : "); scanf("%d%d%d",&n1,&n2,&n3); sum=(n1+n2+n3); avg=(float)sum/(float)3; printf("\n sum of three numbers : %d ",sum); printf("\n average of three numbers : %.3f ", avg); getch(); Output : printf() : The printf() function prints all types of data values to the console. It requires conversion symbol and variable names to print the data. The conversion symbol or control string and variable names should be same in number. Syntax : printf( control strings,var1, var2,..varn);

69 69 Let us consider the following program main() int x=2; float y=2.2; char z= c ; printf( \n %d %f %c,x,y,z); In the above program %d corresponds to x variable, %f to y and %c to z. main() int y=65; clrscr(); printf( %c %d,y,y); Output : A 65 In the above example the integer variable y contains value 65, the variable y is printed using conversion symbols integer and character. As shown in the output, the %c converts numberic 65 value to its corresponding character A. The %d prints the value of 65, as it is, because the variable is of an integer type. Some times if no conversion is possible between two data types ; some garbage value is printed. 1. Write a program to find the average of three real numbers. 2. Write a program to swap the values of two variables using temporary variable or third variable 3. Write a program to swap the values of two variables without using third variable or temporary variable. 4. Write a program to accept the alphabet in lower case and display it in upper case. 5. Write a program to accept a number and calculate square of it. 6. Write a program to accept the radius of circle and calculates its area.( area of circle is PI*R*R, PI= ).

70 70 7. Write a program to find the size of integer variable, character variable, float variable. 8. Write a program to accept the length and breadth of a rectangle and calculate the area of rectangle. 9. The total distance travelled by vehicle in t seconds is given by distance = ut+1/2at*t where u is the initial velocity(m/sec). a is the accerleration(m/sec*sec). Write a C program to find the distance travelled at regular intervals of time given the values of u and a. Program : #include<stdio.h> #include<conio.h> void main() double a,u,t,d; clrscr(); printf("\n Enter the values of initial velocity(u), acceleration(a) and time(t) :"); scanf("%lf%lf%lf",&u,&a,&t); d=u*t+0.5*a*t*t; printf("\n Distance travelled by vehicle = %lf meters",d); getch(); 10. Write a program to calculate slope and midpoint of a line (by giving input as two points). Program : /* program to find the slope and midpoint */ #include<stdio.h> #include<conio.h> main() float x,y,x1,x2,y1,y2,slope; clrscr(); printf("\n Enter first point x1,y1 : "); scanf("%f%f",&x1,&y1); printf("\n Enter second point x2,y2 : "); scanf("%f%f",&x2,&y2); slope=(y2-y1)/(x2-x1);

71 71 x=(x1+x2)/2.0; y=(y1+y2)/2.0; printf("\n slope : %f", slope); printf("\n mid point(x,y) :(%f, %f )",x,y); getch(); 11. Write a program to read the values of x,y and z and print the results of the following expressions a=(x+y+z)/(x-y-z), b = (x+y+z)/3, c=(x+y)(x-y)(y-z) 12. Write a program to display the system current date and time. 13. Write a program to accept the values of a,b,c and calculate b*b-4*a*c 14. Write a program to print the numbers from 1 to 10. ********************************************************************************* ***************************************************************************

72 72 Statements : A statement causes an action to be performed by the program. It translates directly in to one or more executable computer instructions. C defines eleven types of statements. They are : 1. Null Statements 2. Expression Statements 3. Return Statements 4. Compound Statements 5. Conditional Statements 6. Labeled Statements 7. Switch Statements 8. Iterative Statements 9. Break Statements 10. Continue Statements 11. Goto Statements Null Statements The null statement is just a semicolon (the terminator). Eg //null statement Although they do not arise often, there are syntactical situations where we must have a statement but no action is required.in these situations we use the null statement. Expression Statements An Expression is turned in to a statement by placing a semicolon(;)after it. expression; //expression statement Eg : a=2; Return Statement A Return Statement terminates a function. All functions,including main, must have a return statement. Where there is no return statement at the end of the function,the system inserts one with a void return value. return expression; //return statement

73 73 The return statement can return a value to the calling function. In case of main,it returns a value to the operating system rather than to another function. A return value of zero tells the operating system that the program executed successfully. Compound Statement A Compound Statement is a unit of code consisting of zero or more statements.it is also known as a block. The compound statement allows a group of statements to become one single entity. A Compound Statement consists of an opening brace,an optional declaration and definition section,and an optional statement section,followed by a closing brace. Eg: int x; //Local Declarations int y; int z; x=1; //Statements y=2; //End Block The compound statement does not need a semicolon. Selection Statements : A Program is nothing but the execution of sequence of one or more statements. This is known as sequential flow of control. In practical applications there are a number of situations where one has to change the order of the execution of statements based on the conditions. This involves a decision making condition to see whether a particular condition is satisfied or not. If the condition is true then a set of statements are executed otherwise another set of statements are executed. The C language provides a numbers of program control statements or selection statements that can be used to control the way of execution of the program. These include The decision statements : If and switch statements The looping constructs : For, while,do..while

74 74 Decision Making Statements or Conditional Statements C Language possesses Decision Making capabilities by supporting the following statements 1. IF statements 2. Switch 3. Goto The if statements is a powerful decision making statement and is used to control the flow of execution of statements. It is basically a two-way selection or decision statement. It takes the following form : Different forms of If Statements Simple if if..else statement Nested if.else statement else if ladder Simple if : The general form of simple if statement is Syntax : if ( Test Expression ) Statement-block; Statement-x;

75 75 The statement block may be a single or group of statements. if the test expression or condition is true then the statement block will be executed otherwise the statement block will be skipped and the execution will jump to the statement-x. Remember, when the condition is true both the statement-block and the statement-x are executed in sequence. /* program to check wether the given number is less than 10 */ #include<stdio.h> #include<conio.h> main() int num; clrscr(); printf("\n Enter any number < 10 "); scanf("%d",&num); if(num<10) printf("\n Entered number %d < 10",num); getch(); Output : In the above program the values of the variable num is entered through the keybord. The value of num is checked with if statement num<10. If the num value is less than 10 then print the message Entered number 8 < 10. Note: If we want to execute multiple statements in the if statement, that statements must be blocked with in braces.

76 76 /*program to calculate the sum and multiplication using if statement. */ #include<stdio.h> #include<conio.h> main() int n1,n2,i; clrscr(); printf("\n Enter any two number "); i=scanf("%d%d",&n1,&n2); if(i==2) printf("\n Adddition of two numbers : %d ",(n1+n2)); printf("\n Multiplication of two numbers : %d ",(n1*n2)); getch(); Output : The program reads the value of n1,n2 through scanf() function and assigned to variable m. if statement checks the condition and executes the block of statements. if..else statement It is observed that if statement in the previous programs executes only when the condition is true. It does nothing when the condition is false. The if.else statement takes care of true as well as false conditions. it has two blocks. One block is for if and it is executed when the condition is true. The other block is of else and it is executed when the condition is false.

77 77 The else statement cannot be used without if. No multiple else statements are allowed with one if. No semicolon (;) is needed for an if else statement. /* program to find the greatest of two numbers */ #include<stdio.h> #include<conio.h> main() int n1,n2; clrscr(); printf("\n Enter any two numbers "); scanf("%d%d",&n1,&n2); if(n1>n2) printf("\n %d is greater ",n1); else printf("\n %d is greater ",n2); getch();

78 78 /* program to convert a character from lower case to upper case by using predefined functions */ #include<stdio.h> #include<conio.h> #include<ctype.h> main() char ch; clrscr(); printf("\n Enter any alphebet in lower case or upper case "); ch=getchar(); if(islower(ch)) putchar(toupper(ch)); else putchar(tolower(ch)); getch(); /* toupper and tolower are predefined functions from ctype.h file. islower is used to check whether the character is in lowercase or not if it is lower case character then it returns 1 otherwise 0. toupper is used to convert the given character into uppercase. tolower is used to convert the given character into lowercase.*/ output : /* write a program to read the values of a,b,c through the keyboard. add them and after addition check if it is in the range of 100 & 200 or not.*/ #include<stdio.h> #include<conio.h> main() int a,b,c,d; clrscr(); printf("\n Enter three numbers :"); scanf("%d%d%d",&a,&b,&c); d=a+b+c; if(d<=200 && d>=100) printf("\n sum is %d which is in between 100 & 200 ",d); else printf("\n sum is %d which is out of range ",d); getch(); Output :

79 79 Nested If : When a series of if..else statements are occurred in a program. We can write one if..else statement in another if else statement called nested if. (simple if else within another if else is referred as nested if. /* program to illustrate Nested If*/ #include<stdio.h> #include<conio.h> main() int a,b; clrscr(); printf("\n Please Enter two integers : "); scanf("%d%d",&a,&b); if(a<=b) if(a<b) printf(" \n %d < %d ",a,b); else printf("\n %d == %d ",a,b); else printf("\n %d > %d ",a,b); getch(); Output :

80 80 /* program to find greatest of three numbers */ #include<stdio.h> #include<conio.h> main() int a,b,c; clrscr(); printf("\n Enter any three numbers "); scanf("%d%d%d",&a,&b,&c); if(a>b) if(a>c) printf("\n %d is greater ",a); else printf("\n %d is greater ",c); else if(b>c) printf("\n %d is greater ",b); getch(); Output : Write a program to find whether the given number is even or odd. Write a program to find the roots of an quadratic equation. If else ladder There is another way of putting ifs together when multipath decisions are involved. A multipath decision is a chain of ifs in which the statement associated with each else is an if.

81 81 The conditions are evaluated from the top, downwards. As soon as condition is found to be true, statement associated with it is executed. When all the n conditions become false, then the final else containing the default statement will be executed. /* write a program to accept a character and check whether it is vowel or consonant or digit or special symbol*/ #include<stdio.h> #include<conio.h> main() char ch; clrscr(); printf("\n Enter any character "); scanf("%c",&ch); if(ch=='a' ch=='e' ch=='i' ch=='o' ch=='u') printf("\n ***********v o w E L **************"); else if(ch=='a' ch=='e' ch=='i' ch=='o' ch=='u') printf("\n***********v o w E L ************** "); else printf("\n ***********C O N S O N A N T**************"); getch(); Output :

82 82 Switch Statement : Switch is a multi-way decision statement in C. In general switch statement can be used as an alternative to if else statement. Switch can be used when we know the exact value of a variable. Whereas if else can be used when we know either exact value or range of values for a variable. Switch statement tests the value of a given variable or result of the expression against a list of case values and when a match is found a block of statements associated with that case is executed. The expression or variable must be an integer or character type. Value1, Value2. are constants or expressions are known as case labels. case labels must end with a colon. block I block II are the statement blocks and may contain zero or more statements. When the switch is executed the value of expression is successively compared against the values. If a case is found whose value matches with the value of the expression then the block of statements that follows the case are executed. The break statement signals the end of a particular case. When the break statement is executed program control immediately exits from the switch statement. The default is an optional case. If no match is found in that case default block will be executed if it present, if doesn t present no action takes place. /* write a program to check whether the entered character is consonant or vowel */

83 83 #include<stdio.h> #include<conio.h> void main() char ch; clrscr(); printf("\n Enter any character "); scanf("%c",&ch); switch(ch) case 'a' : case 'e' : case 'i' : case 'o' : case 'u' : case 'A' : case 'E' : case 'I' : case 'O' : case 'U' : printf("\n Vowel "); break; default : printf("\n Consonant "); break; getch(); Output : /*write a program to perform arithmetic operation using switch statement*/ #include<stdio.h> #include<conio.h> main() int a,b,res,choice; clrscr(); printf("\n O P E R A T I O N S "); printf("\n 1.Addition(+) : "); printf("\n 2.Subtraction(-) : "); printf("\n 3.Multiplication(*) : "); printf("\n 4.Division(/) : "); printf("\n Enter U R Choice "); scanf("%d",&choice);

84 84 switch(choice) case 1 : printf("\n Enter any two numbers "); scanf("%d%d",&a,&b); res=a+b; printf("\n Sum of two numbers : %d ",res); break; case 2 : printf("\n Enter any two numbers "); scanf("%d%d",&a,&b); res=a-b; printf("\n Difference of two numbers : %d ",res); break; case 3 : printf("\n Enter any two numbers "); scanf("%d%d",&a,&b); res=a*b; printf("\n Product of two numbers : %d ",res); break; case 4 : printf("\n Enter any two numbers "); scanf("%d%d",&a,&b); res=a/b; printf("\n Division of two numbers : %d ",res); break; default : printf("\n U Selected an invalid choice "); getch(); Output :

85 85 Repetitive Statements or Looping Statements: Looping is a process of repeated execution of block of statements until the condition for its termination is satisfied. A loop therefore consists of two segments, one is body of the loop and other one is condition known as control statement. A looping generally contains the following 4 steps o Setting and initialization of a counter variable o Test for a specified a condition for execution of the loop o Execution of the statements in the loop o Incrementing the counter variable Depending the position of control statement (condition) in the loop a control structure may be classified as either entry controlled loop or exit controlled loop. In the entry controlled loop condition is tested before body of loop get executed. In exit controlled loop condition is tested at the end of the body of the loop and therefore the body is executed unconditionally for the first time. The C language provides the following three loop constructs for performing loop operations 1. The while statement 2. The do statement 3. The for statement While Loop : while is an entry controlled loop. First condition is evaluated if it is true then body of the loop is executed. After executing the body, condition is once again evaluated,if it is true body is executed once again. This process continues as long as condition is true. The body of the loop may have one or more statements. Note: The braces are not required if body contains only one statement.

86 86 Programs 1. write a program to print the numbers from 1 to write a program to print first ten numbers and their squares. 3. write a program to find the sum of numbers from 1 to n( the value of n is accepted from the keyboard) 4. write a program to find the factorial of a given number 5. write a program to find the sum of all digits in a given number 6. write a program to Reverse of a given number 7. write a program to check whether the given number is palindrome or not 8. write program to print Fibonacci series 9. Write a program to find GCD/HCD and LCM of two numbers

87 87 /* write a program to print the numbers from 1 to 100*/ Explanation : 1 2..up to 100. #include<stdio.h> #include<conio.h> main() int i=1; clrscr(); printf("\n Numbers from 1 to 100 "); while(i<=100) printf("\n %d",i); i++; getch(); Output: /* write a program to print first ten numbers and their squares*/ Explanation : up to Output: #include<stdio.h> #include<conio.h> main() int i=1; clrscr(); printf("\n Number \t Square"); while(i<=10) printf("\n %d \t\t %d",i,(i*i)); i++; getch(); /*write a program to find the sum of numbers from 1 to n( the value of n is accepted from the keyboard)*/ Output : suppose the value of n is 10 then the output must be =55 #include<stdio.h> #include<conio.h> main() int i=1,n,sum=0; clrscr();

88 88 printf("\n Enter any number "); scanf("%d",&n); while(i<=n) sum=sum+i; i++; printf("\n sum of all numbers from 1 to %d is : %d ",n,sum); getch(); Output : /*write a program to find the factorial of a given number*/ Explanation : 5! = 5*4*3*2*1 = 120 #include<stdio.h> #include<conio.h> main() int i=1,n,sum=0; clrscr(); printf("\n Enter any number "); scanf("%d",&n); while(i<=n) sum=sum+i; i++; printf("\n sum of all numbers from 1 to %d is : %d ",n,sum); getch(); Output : /* write a program to display the multiplication table*/ #include<stdio.h> #include<conio.h> main() int i=1,n,mul=1; clrscr(); printf("\n Enter any number "); scanf("%d",&n); printf("\n Multiplication Table for %d ",n); while(i<=12) Output :

89 89 printf("\n %d * %d = %d ",n,i,n*i); i++; getch(); /* write a program to find the sum of all digits in a given number*/ Explanation : let us consider n=123 then we need find sum of all digits in it i.e, 1+2+3=6 #include<stdio.h> #include<conio.h> main() int n,sum=0,rem=0,n1; clrscr(); printf("\n Enter any number "); scanf("%d",&n); n1=n; while(n>0) rem=n%10; sum=sum+rem; n=n/10; printf("\n Sum of digits in %d numbers is %i ",n1,sum); getch(); Output : /* write a program to Reverse of a given number */ Explanation : suppose the number is 256 then display it in reverse order 652 #include<stdio.h> #include<conio.h> main() int n,rev=0,rem=0,n1; clrscr(); printf("\n Enter any number "); scanf("%d",&n); n1=n; while(n>0) rem=n%10; rev=rev*10+rem; n=n/10; printf("\n Reverse of %d is %d ",n1,rev); getch();

90 90 Output : /* write a program to check whether the given number is palindrome or not*/ Explanation : the number is said to be palindrome if and only if the reverse of that number must equal to that number. Let us consider n=121 reverse of n is 121, Hence the reverse of n is same as n then n is called palindrome number. #include<stdio.h> #include<conio.h> main() int n,rev=0,rem=0,n1; clrscr(); printf("\n Enter any number "); scanf("%d",&n); n1=n; while(n>0) rem=n%10; rev=rev*10+rem; n=n/10; if(rev==n1) printf("\n %i is palindrome ",n1); else printf("\n %d is not a palindrome ",n1); getch(); Output : /* write program to print Fibonacci series*/ #include<stdio.h> #include<conio.h> main() int n,f1=0,f2=1,f3,i=2; clrscr(); printf("\n Enter any number "); scanf("%d",&n); printf("\n Fibonacii Series :"); printf("\n %d\t%d",f1,f2); while(i<n)

91 91 f3=f1+f2; f1=f2; f2=f3; printf("\t%d",f3); i++; getch(); Output : /*write a program to find GCD/HCF and LCM of given two numbers */ #include<stdio.h> #include<conio.h> main() long int n1,n2,a,b; clrscr(); printf("\n GCD/HCF & LCM OF TWO NUMBERS"); printf("\n\n\tenter TWO NUMBERS: "); scanf("%ld %ld",&n1,&n2); a=n1;b=n2; while(n1!=n2) if(n1>n2) n1=n1-n2; else n2=n2-n1; printf("\n GCD/HCF Of Two Numbers is: %ld",n1); printf("\n LCM Of Two Numbers is : %ld",(a*b)/n1); getch();

92 92 do while: do-while is exit controlled loop. In some cases it might be compulsory to execute the body of the loop before the test is performed. Such situations can be handled with the help of the do statement. It is also repetitive statement and executes the body of the loop once irrespective of the condition, then checks the condition and continues the execution until the condition becomes false. Write a program to find average of N numbers Write a program to two numbers using do while For Statement : For is an another entry controlled loop. The general form of the for loop is Syntax : for ( initialization ; testcondition ; incr/decr ) body of the loop The execution of the for statement is as follows: Initialization of control variables is done first. Now the value of the variable is tested using test condition. If the test condition is true body of the loop is executed otherwise loop is terminated. After executing the body of the loop, control is transferred to increment/decrement block. Test condition is once again evaluated, and if it is true body is executed once again.

93 93 This process continues till value of the control variable fails to satisfy the condition. Program based on For Loops : 1. Write a program to check whether the given numbers is prime or not. 2. Write a program to find sum of even numbers, count of even numbers,sum of odd numbers, count of odd numbers from 1 to Write a program to check whether the given number is Armstrong or not. 4. Write a program to check whether a number is perfect square or not 5. Write a program to find X to power of N 6. Write a program to display numbers from 9 to1 and their square roots 7. Write a program to find sum of the following series 1^2+2^2+3^2+4^2+ n^2 8. Write a C program to read in two numbers, x and n, and then compute the sum of this geometric progression: 1+x+x2+x3+.+xn For example: if n is 3 and x is 5, then the program computes write a c program to calculate the following sum: Sum=1-x2/2! +x4/4!-x6/6!+x8/8!-x10/10!*/ /*write a program to check whether the given number is prime or not*/ #include<stdio.h> #include<conio.h> main() int count=0,i=1,n; clrscr(); printf("\n Enter any number "); scanf("%d",&n); for(i=1;i<=n;i++) if(n%i==0) count++; if(count==2) printf("\n %d is prime number ",n); else printf("\n %d is not prime number ",n); getch(); Output : /*write a program to print all even numbers from 1 to 100 and also print sum and count of all even number */ #include<stdio.h> #include<conio.h>

94 94 main() int i,count=0,sum=0; clrscr(); printf("\n All Even Numbers from 1 to 100 "); for(i=1;i<=100;i++) if(i%2==0) printf("\t %d",i); sum=sum+i; count++; printf("\n Sum of all Even Numbers from 1 to 100 is %d ",sum); printf("\n Count of all Even Numbers from 1 to 100 is %d ",count); getch(); Output: /* write a program to check whether the given number is Armstrong or not*/ #include<stdio.h> #include<conio.h> main() int rem=0,sum=0,n,n1; clrscr(); printf("\n Enter any number "); scanf("%d",&n); n1=n; for(;n>0;n=n/10) rem=n%10; sum=sum+rem*rem*rem;

95 95 if(sum==n1) printf("\n %d is Armstrong ",n1); else printf("\n %d is not Armstrong ",n1); getch(); Output : /* write a program to check whether the number is perfect or not */ #include<stdio.h> #include<conio.h> void main() long int n,i=1,perfect=0; clrscr(); printf("\nenter a number: "); scanf("%ld",&n); while(i<n) if(n%i==0) perfect+=i; i++; if(perfect==n) printf("\n%ld is perfect",n); else printf("\n%ld is not perfect",n); getch(); Output : /* write a program to find x to the power of N*/ #include<stdio.h> #include<conio.h> main() long int x,n,i,res=1; clrscr(); printf("\n Enter X & N "); scanf("%ld%ld",&x,&n);

96 96 for(i=0;i<n;i++) res=res*x; printf("\n %ld^%ld is %ld ",x,n,res); getch(); Output : /* write a program to print numbers from 9 to 1 and display their square root*/ #include<stdio.h> Output : #include<conio.h> #include<math.h> main() int i; clrscr(); printf("\n====================================="); printf("\n\tnumber\tsquare Root"); printf("\n====================================="); for(i=9;i>0;i--) printf("\n\t%d\t%.2f",i,sqrt(i)); getch(); Unconditional Statements : Break and continue Statements : There are two statement built in C, break; and continue; to interrupt the normal flow of control of a program. Loops performs a set of operation repeately until certain condition becomes false but, it is sometimes desirable to skip some statements inside loop and terminate the loop immediately without checking the test expression. In such cases, break and continue statements are used. In C programming, break is used in terminating the loop immediately after it is encountered. The break statement is used with conditional if statement. Synatx of Break statement : break; The break statement can be used in terminating all three loops for, while and do...while loops.

97 97 The figure below explains the working of break statement in all three type of loops. Example of Break Statement : Write a C program to find average of maximum of n positive numbers entered by user. But, if the input is negative, display the average(excluding the average of negative input) and end the program. /* C program to demonstrate the working of break statement by terminating a loop, if user inputs negative number*/ # include <stdio.h> int main() float num,average,sum; int i,n; printf("maximum no. of inputs\n"); scanf("%d",&n); for(i=1;i<=n;++i) printf("enter n%d: ",i); scanf("%f",&num); if(num<0.0) break; //for loop breaks if num<0.0 sum=sum+num; average=sum/(i-1); printf("average=%.2f",average); return 0;

98 98 Output : Maximum no. of inputs 4 Enter n1: 1.5 Enter n2: 12.5 Enter n3: 7.2 Enter n4: -1 Average=7.07 In this program, when the user inputs number less than zero, the loop is terminated using break statement with executing the statement below it i.e., without executing sum=sum+num. In C, break statements are also used in switch...case statement. It is sometimes desirable to skip some statements inside the loop. In such cases, continue statements are used. Continue Statement : Syntax of continue statement : Continue; Just like break, continue is also used with conditional if statement. For better understanding of how continue statements works in C programming. Analyze the figure below which bypasses some code/s inside loops using continue statement.

99 99 Example of continue statement : Write a C program to find the product of 4 integers entered by a user. If user enters 0 skip it. //program to demonstrate the working of continue statement in C programming # include <stdio.h> int main() int i,num,product; for(i=1,product=1;i<=4;++i) printf("enter num%d:",i); scanf("%d",&num); if(num==0) continue; / *In this program, when num equals to zero, it skips the statement product*=num and continue the loop. */ product*=num; printf("product=%d",product); return 0; Output : Enter num1:3 Enter num2:0 Enter num3:-5 Enter num4:2 product=-30 goto statement : C supports the go to statement to branch unconditionally from one point to another in the program. Although it may not be essential to use the go to statement in a highly structured language like C, there may be occasions when the use of go to might be desirable. The goto requires a label in order to identify the place where the branch is to be made. A label is any valid variable name, and must be followed by a colon. The label is placed immediately before the statement where the control is to be transferred. The general forms of goto and label statements are shown below : goto label; label : statements; statements; ; lable : statements; goto label;

100 100 Example of goto statement : /* write a program to check whether the given number is even or odd */ #include<stdio.h> #include <stdlib.h> #include<conio.h> void main() int x; clrscr(); printf("\n Enter any Number "); scanf("%d",&x); if(x%2==0) goto even; else printf("\n %d is Odd Number "); exit(0); even : printf("\n %d is Even Number ",x); return; Output : /* write a program to check whether entered year is a leap year or not */ #include<stdio.h> #include<conio.h> void main() int year; clrscr(); printf("\n Enter any year : "); scanf("%d",&year); if(year%4==0) goto leap; else goto nonleap; leap : printf("\n %d is a leap year ",year); return; nonleap : printf("\n %d is not a leap year ",year); return; getch(); Output :

101 101 Previous Year Question Papers 1. (a) Explain in detail about different data types available in C. (b) Write the structure of a `C' program and explain. R07 Supply December (a) Discuss the History of `C' language. (b) Write the structure of `C' program and explain. R07 Supply December (a) Explain the types of operators available in C? (b) Write a C program with Exclusive OR operation between the two integers and display the result? R09 Supply December (a) Explain different categories of an algorithm with an example? (b) What are the differences between signed and unsigned data types, list out them? R09 JAN (a)what is meant by compilation? Explain in detail? (b) What are the C keywords? Elaborate them? R09 JAN (a) What are unary operators and their uses? Describe logical operators with their return values? (b) Write a C program to shift inputted data by 2 bits left? R09 JAN (a) Define Algorithm and Flow Chart? (b) A utility company charges its customers based on their monthly utilization in terms of units as follows: Description charge: First 100 units Rs.10 per unit Next 200 units Rs. 9 per unit Next 200 units Rs.8 per unit Next units Rs.7 per unit Write an Algorithm and flowchart that reads monthly units of a customer and output the charge amount. R09 JAN (a) What are various conditional and bitwise operations in C, explain them with an example? (b) Explain various looping statements in C language with example? R09 JAN What are various arithmetic and assignment operators in C, explain them with an example. R09 JAN ( a) Define the flow chart? Draw a flow chart for finding roots of a quadratic equation with all cases? (b) What are various conditional and relational operators in C, explain them with an example. R09 JAN ( a) Explain the control statements in C language with an example? (b) Explain various looping statements in C language with example R09 JAN (a) Explain and specify the interactions between various components that support the basic functionality of a computer? (b) Discuss in detail the program execution steps? [7+8] R09 DEC (a) List the basic data types, their sizes and range of values supported by C language? (b) Describe the purpose of commonly used conversion characters in scanf() function? (c) Explain the only ternary operator available in C with illustrative example? R09 DEC (a)Define Algorithm? What are the characteristics that any algorithm should satisfy? (b) Draw a flowchart for finding maximum of given three integers? (c) Differentiate between compiler and interpreter? [7+4+4] 15.( a) Differentiate between if-else-if ladder and switch statement?

102 102 (b) What is the implicit type conversion hierarchy that is applied while evaluating expressions? (c) List and give examples for different bitwise operators available in C?R09 DEC 2010 set (a) Differentiate between application software and system software? (b) Draw a flowchart for finding the sum of n numbers starting from 1? (c) Briefly discuss various computing environments with neat diagrams? R09 DEC 2010 set 3 17.(a) What do you mean by operator precedence and associativity? How one can override the precedence defined by C language? Give illustrative examples? (b) Explain the structure of a C program? R09 DEC 2010 set 3 18.(a) List the activities involved in each phase of waterfall system development life cycle model? (b) What are the different types of errors one can encounter during the program execution? [10+5] R09 DEC 2010 set 4 19.( a) What is an identifier? What are the naming rules for identifiers in C? (b) List different categories of C operators based on their functionality? Give examples? (c) Explain different types of coding constants in a C? R09 DEC 2010 set (a) Explain the functions of the following: (i) Preprocessor (ii) Compiler (iii) Linker. b) Draw a flowchart to find maximum and minimum of the given three input numbers.r09 June 2010 set-1 21.(a) Write minimal C-expressions for the following: i)3x4+5x3-4x2+7x+20 ii) abcbccaab iii) Digit at 100 s place of the given integer x. (Ex. Digit at 100 s place in 2578 is 5). iv) If a > b then the value of expression is a-b, otherwise b-a v) True if 5 <, otherwise false x < 10 vi) Divide the integer variable x by 16 using bit-wise operators (b) What is the difference between the following c-words? (i) amount and amount (ii) 200 and (c) A number is said to be prime, if it is not exactly divisible by any other numbers other than 1 and the number it self. For example 7 and 11 are primes. Write C- language program that reads a number from input and determine whether it is a prime or not. [6+2+7] R09 June 2010, set-1 22.(a)List out the various steps in software development. (b) Given the 3 sides of triangle a, b and c as input, Draw a flowchart to test whether it is isosceles, equilateral or not. It should also validate whether the input forms a triangle or not. (Ex. 10, 3, 3 is not a triangle) [6+9] R09 June 2010, set-2 23.(a) Write minimal C-expressions for the following: i) 5a +3a -4a +6a+12 ii) abcbccaab iii) If the given integer value of x is treated as binary, the fifth bit from the right. iv) Absolute value of variable x. v) True if x is exactly divisible by 5 but not divisible by 3, otherwise false. vi) Subtract x from y and then increment x. (b) What is the difference between the following C-words? i) 253 and 0253

103 103 ii) r and \r (c) Write C-program for determining whether the given integer at input is perfect number or not. A number is said to be perfect number if the sum of factors is equal to number itself. For example, the factors of 6 are 1, 2, 3 whose sum 1+2+3=6. R09 June 2010, set-2 24(a) What is an algorithm? List and explain the properties of algorithm. (b) A utility company charges its customers based on their monthly utilization in terms of units as follows: Description charge First 100 units Rs.10 per unit Next 200 units Rs. 9 per unit Next 200 units Rs.8 per unit Next units Rs.7 per unit Write flowchart that reads monthly units of a customer and output the charge amount. [7+8] R09 June 2010, set-3 25.(a) Write minimal C- expressions for the following: i) 6b +3b -5b +6b+15 ii) 2234abccab iii) Increment x and then add to z iv) Maximum of the values of 3 variables a, b and c v) True if the value of character variable c is in uppercase, otherwise false vi) Rightmost octal digit in the value of integer variable x (b) What is the difference between the following C-words? (i) 5 and 5 (ii) if and ++ (c) Write C-program for generation of multiplication table for the given integer input x. For example, if input is 5, the program need to output 5X1=5 5 X 2 = X10 =50 R09 June 2010, set (a) List and explain the functions of various parts of computer hardware. (b) A university gives grades based on the percentage of marks obtained in the examinations as follows: Percentage of marks Grade 70 and above Distinction 60 and above but below 70 First 50 and above but below 60 Second 40 and above but below 50 Third below 40 Fail Write a flowchart that inputs the percentage marks and output the division. [6+9] R09 june2010 set4 27.a) Write minimal C- expressions for the following: i) 6a +3a -5a -6a+22 ii) 1235abbc+

104 104 iii) Equivalent to C-statement while (a > = b)a = a-b where a and b are unsigned integers. iv) True if x/y >3 without zero divide, false otherwise v) If x<y then -1 else if x = = y then 0 else 1(use ternary operator) vi) Fourth bit from the right if the number x is treated in binary representation. (b) What is the difference between the following C-words? i) count and int ii) 526 and 526 (c) Write C-program that reverses the decimal digits of integer value at input. For example, for input 5379, the program need to output R09 june2010 set-4 28.(a) What is an algorithm? Write an algorithm to read five integers and find out if the values are in ascending order.b) Draw a flow chart to read ten integer values and print the sum of squares of the values.r09 June-11 s1 29.(a) Write minimal C expressions for the following: (i) 2x + 3x - 4x + 7x -10 (ii) Digit at the 10's place of the given positive integer x (for example, digit at the 10's place in 3458 is 5) (iii) True if the given positive integer x is odd, false otherwise (iv) Add x to y, and then decrement x (v) True if 5 <= a <= 10, false otherwise (vi) Fourth bit from the right if the number x is treated in binary representation. (b) Write a complete C Program to print all the prime numbers between 1 and n. Where n is the value supplied by the user. R09 June-11 s1 30.(a) What is an algorithm? Write an algorithm to find out if a given number is a prime. (b) Draw a flow chart to read ten positive integers and print how many are multiples of 7. R09 June-11 s2 31(.a) Write minimal C expressions for the following: (i) 3x + x - 4x + 7x (ii) Maximum of the values of three variables a, b and c (iii) Digit at the 100's place of the given positive integer x (for example, digit at the 100's place in 3458 is 4) (iv) True if the given positive integer x is even, false otherwise (v) Increment x, and then add to z (vi) True if the given positive integer x is a multiple of 3 and 7, false otherwise. (b) What are the bitwise operators in C? Explain the same with examples. R09 June-11 s2 32.(a) Write an algorithm to find out all the factors of a given positive integer. (b) What is a flow chart? Draw a flow chart to read ten integers and print the sum of squares of all ten values. [8+7] R09 June-11 s3 33.(a) Write minimal C expressions for the following: 3 2 (i) x - 4x + 7x -12 (ii) Absolute value of (a-b) (iii) Remainder when unsigned integer variable x is divided by 8, using bitwise operators. (iv) True if the given positive integer x is even and is also a multiple of 7, false otherwise. (v) Minimum of the values of three variables a, b and c. (vi) True if the given character variable c represents a numeral (that is '0'...'9'), false otherwise. R09 June-11 s3

105 (a) Write an algorithm to read ten positive integers and find out how many are perfect squares (such as 49, 81). You may assume that the input values read are in the range 1 to (b) List the various steps in software development. [8+7] R09 June-11 s4 2.(a) Write minimal C expressions for the following: 3 2 (i) x -3x + 3x -1 (ii) Digit at the 10's place of the given positive integer x (for example, digit at the 10 s place in 3458 is 5) (iii) True if the given positive integer x is a multiple of both 17 and 11, false otherwise. (iv) Remainder when unsigned integer variable x is divided by 8, using bitwise operators. (v) True if 25 > a 10, false otherwise (vi) Second bit from the right if the number x is treated in binary representation. b) Write a complete C Program to read ten integers and find: (i) The number of even integers and their sum, and (ii) The number of odd integers and their sum. R09 June-11 s4 (R09 DEC 2012) (R09 JUNE 2012) OBJECTIVE QUESTIONS: