At the end of this module, the student should be able to:
|
|
- Agatha Mitchell
- 6 years ago
- Views:
Transcription
1 INTRODUCTION One feature of the C language which can t be found in some other languages is the ability to manipulate pointers. Simply stated, pointers are variables that store memory addresses. This is the topic of this module. The ability to handle pointers allows great flexibility and makes C also suitable for writing systems programs.
2 OBJECTIVES At the end of this module, the student should be able to: 1. explain what a pointer is; 2. use pointer operators in a program; and 3. use pointers as function parameters.
3 Pointers directly deal with memory storage locations and addresses. It is necessary that we have a good understanding of the memory s structure. The exact structure varies from one machine to another.
4 The main memory can be viewed as a sequence of storage locations. Each location is capable of storing 1 byte of data, and the locations are numbered starting from zero Fig. 6.1 Conceptual View of the main memory
5 The size of the main memory varies. It can be as small as 4 megabytes (4*1024*1024 bytes) or as large as 64 megabytes (64*1024*1024 bytes). The number associated with each memory location is called the address of that location. When a program is run, each variable defined in the program is assigned to a unique memory location. The memory location is used to store the value of that variable.
6 #include <stdio.h> int x, y; float ratio; main( ) { printf( enter two integers: ); scanf( %d %d, &x, &y); ratio = x/(float) y; printf( ratio = %f\n, ratio); } In most systems, an integer value occupies 2 bytes (or 16 bits) while a float value occupies 4 bytes (2 for the mantissa and 2 for the exponent).
7 variables x, y, and ratio are assigned to different memory locations. All values stored in the memory are in binary. Suppose that the numbers 10 and 20 are inputted. This stores 10 in x, 40 in y, and 0.25 in ratio. In binary, 10, 40 and 0.25 are , , and , respectively.
8 These binary representations are stored in the memory locations of the variables x y ratio Fig. 6.2 Byte values stored In memory locations of variables
9 For our purposes, we will use a simplified presentation. We ll assume that each data item occupies exactly one memory location, and we ll write values in decimal instead of binary x y ratio Fig. 6.3 Simplified representation Of main memory
10 One of the main strengths of the C language is its ability to use memory addresses to access variables. This is done with the use of pointer variables and two unary operators: 1) the indirection operator, *, and 2) the address operator, &. A pointer variable (simply called a pointer) is a variable that can store the memory address of another variable.
11 The format of defining a pointer variable is: data-type *variable-name; For example, in the definition int *p; int x, y; float *t, ratio; p is a pointer which can store the memory address of an integer variable, and t is another pointer capable of storing the memory address of a float.
12 To obtain the memory address of a variable, we use the address operator, & Thus, the statements p = &x; t = ∶ stores the memory address of x in p, and the address of ratio in t. p is now said to point to x, while t points to ratio.
13 To illustrate, suppose that all the variables defined were assigned to memory locations, Then, the statement p = &x; stores 0001 in p, and the statement t = ∶ stores 0004 in t Fig 6.4. Contents of main memory showing p pointing to x and t pointing to ratio p x y t ratio
14 The indirection operator, *, is used to access the value of the variable pointed to by a pointer. For example, y = *p; sets y to whatever value stored in address 0001 (which is occupied by x, the variable pointed to by p). Also, printf( %f\n, *t); outputs the value of ratio.
15 We can now access a variable in 2 ways: 1) by using a pointer 2) by using the variable name itself For example, the statements: *p = *p + 2; and x = x + 2; have the same effect they increment x by 2.
16 Take note that a pointer can point only to a particular data type as specified in its definition. It is wrong to write t = &y; since t is a pointer to float while y is an integer variable. Also, since pointers are variables, we can assign a pointer to a pointer. So if p and q are both pointers of the same type, the statement p = q; makes p point to where q currently points.
17 For example, q = &x; p = q; makes both p and q point to x. Below are more examples. int x, y, *p, *q; x = 10; p = &x; /* p points to x */ q = p; /* q points to where p points */ *q = 2; /* stores 2 in x */ p = &y; /* p points to y */ *p = *q; /* stores 2 in y */ (*p)++; /* increments y by 1 */
18 Like ordinary variables, a pointer variable can be assigned to a pointer value only if they are of the same type. The statement q = p; is invalid if p and q are defined as int *p; float *q; There is an exception, however. C provides a generic pointer type, void *, which can be assigned with any pointer type. For example, given the following definitions, int *p, *q, x; void *k; these are valid statements: p = &x; k = (void *) p; q = (int *) k; The result is that both p and q now points to x.
19 When assigning pointer values to and from a generic pointer, type casts are necessary so that the pointer values are stored properly. One common mistake committed by inexperienced programmers is the use of uninitialized pointers. For example, suppose p is defined as: int *p; At the start of the program, p does not point to any variable, so it is incorrect to immediately use the expression *p. Executing a statement such as *p = 10; causes an error.
20 Some uses of pointers: 1) pointers are widely used in handling dynamic variables. 2) pointers are used to access local variables from other functions. Recall: local variables defined within a function cannot be used by other functions.
21 For example, the program #include <stdio.h> compute_circ( ) { circ = 2*3.14*radius; } compute_area( ) { area = 3.14*radius*radius; } main( ) { float radius, circ, area; printf( Input radius: ); scanf( %f, &radius); compute_circ( ); printf( circum. = %f\n, circ); compute_area( ); printf( area = %f\n, area); } will generate errors during compilation because radius, circ and area are local variables and thus cannot be used in functions other than main.
22 A smart way to access local variables from other functions is to use pointers. By passing memory addresses as parameters, local variables defined outside a function can be accessed using the indirection operator, *. The program below shows a modified version of the program above. It uses pointer parameters.
23 #include <stdio.h> compute_circ(int *r, int *c) { *c = 2*3.14*(*r); } compute_area(int *r, int *a) { *a = 3.14*(*r)*(*r); } main( ) { float radius, circ, area; printf( Input radius: ); scanf( %f, &radius); compute_circ(&radius, &circ ); printf( circum. = %f\n, circ); compute_area(&radius, &area); printf( area = %f\n, area); } Notice that the formal parameters were defined as pointers and in the function calls, memory addresses were passed as parameters. As a result, the expression *r in functions compute_circ and compute_area refer to the local variable radius defined in main. Similarly, *c and *a refer to the variables circ and area, respectively.
24 This is better illustrated by picturing the main memory. Let s show how the memory is updated while the program is being executed. Initially, local variables are mapped to unique memory locations, as shown below. Let s say that the user inputted radius circ area
25 When the function call to compute_circ was made, parameters r and c are likewise mapped to some memory locations. The function call passed the memory addresses of radius and circ as parameters, and so r and c point to radius and circ, respectively radius circ area r c
26 Inside the function, the local variables radius and circ are accessed (through pointers) as *r and *c. The same thing happens in compute_area, with radius and area accessed as *r and *a. Now, isn t that neat? We were able to access local variables from outside the function!
27 A commonly-used function that you will probably encounter is the swap function. The swap function is used the exchange the values of two variables and is written as: void swap(int *a, int *b) { int temp; temp = *a; *a = *b; *b = temp; } We are assuming here that the values are integers. To swap the contents of two integer variables, say x and y, we simply make the function call swap(&x, &y);
28 Let us take a moment to scrutinize the function. Pointer parameters are used here to access the variables defined outside the function. In the example above, *a refers to x while *b refers to y. Now, can you see why an ampersand is placed before the variable in a scanf statement? Because actually, scanf is a function. As we know, it s job is to get input from the keyboard and store it in the variable. But we have to pass the address of the variable so that scanf can access and place the value there.
29 In C, and in other languages as well, variables are mapped to specific locations in the main memory. Each memory location has an address, and variables can be accessed through their memory address. C provides a pointer data type and pointer-related operators that allow the access of variables through their memory addresses. This gives the programmer much flexibility and makes C appropriate for writing systems software.
Actually, C provides another type of variable which allows us to do just that. These are called dynamic variables.
When a program is run, memory space is immediately reserved for the variables defined in the program. This memory space is kept by the variables until the program terminates. These variables are called
More informationCS113: Lecture 5. Topics: Pointers. Pointers and Activation Records
CS113: Lecture 5 Topics: Pointers Pointers and Activation Records 1 From Last Time: A Useless Function #include void get_age( int age ); int age; get_age( age ); printf( "Your age is: %d\n",
More informationExpressions. Arithmetic expressions. Logical expressions. Assignment expression. n Variables and constants linked with operators
Expressions 1 Expressions n Variables and constants linked with operators Arithmetic expressions n Uses arithmetic operators n Can evaluate to any value Logical expressions n Uses relational and logical
More informationFundamentals of Programming Session 4
Fundamentals of Programming Session 4 Instructor: Reza Entezari-Maleki Email: entezari@ce.sharif.edu 1 Fall 2011 These slides are created using Deitel s slides, ( 1992-2010 by Pearson Education, Inc).
More informationDECLARAING AND INITIALIZING POINTERS
DECLARAING AND INITIALIZING POINTERS Passing arguments Call by Address Introduction to Pointers Within the computer s memory, every stored data item occupies one or more contiguous memory cells (i.e.,
More informationComputer System and programming in C
1 Basic Data Types Integral Types Integers are stored in various sizes. They can be signed or unsigned. Example Suppose an integer is represented by a byte (8 bits). Leftmost bit is sign bit. If the sign
More informationFirst of all, it is a variable, just like other variables you studied
Pointers: Basics What is a pointer? First of all, it is a variable, just like other variables you studied So it has type, storage etc. Difference: it can only store the address (rather than the value)
More informationThese are reserved words of the C language. For example int, float, if, else, for, while etc.
Tokens in C Keywords These are reserved words of the C language. For example int, float, if, else, for, while etc. Identifiers An Identifier is a sequence of letters and digits, but must start with a letter.
More informationGoals of this Lecture
C Pointers Goals of this Lecture Help you learn about: Pointers and application Pointer variables Operators & relation to arrays 2 Pointer Variables The first step in understanding pointers is visualizing
More informationFundamentals of Programming. Lecture 3: Introduction to C Programming
Fundamentals of Programming Lecture 3: Introduction to C Programming Instructor: Fatemeh Zamani f_zamani@ce.sharif.edu Sharif University of Technology Computer Engineering Department Outline A Simple C
More information3. EXPRESSIONS. It is a sequence of operands and operators that reduce to a single value.
3. EXPRESSIONS It is a sequence of operands and operators that reduce to a single value. Operator : It is a symbolic token that represents an action to be taken. Ex: * is an multiplication operator. Operand:
More informationProgramming for Engineers Introduction to C
Programming for Engineers Introduction to C ICEN 200 Spring 2018 Prof. Dola Saha 1 Simple Program 2 Comments // Fig. 2.1: fig02_01.c // A first program in C begin with //, indicating that these two lines
More informationLanguage comparison. C has pointers. Java has references. C++ has pointers and references
Pointers CSE 2451 Language comparison C has pointers Java has references C++ has pointers and references Pointers Values of variables are stored in memory, at a particular location A location is identified
More informationComputer Programming Lecture 12 Pointers
Computer Programming Lecture 2 Pointers Assist.Prof.Dr. Nükhet ÖZBEK Ege University Department of Electrical & Electronics Engineering nukhet.ozbek@ege.edu.tr Topics Introduction to Pointers Pointers and
More informationParameter passing. Programming in C. Important. Parameter passing... C implements call-by-value parameter passing. UVic SEng 265
Parameter passing Programming in C UVic SEng 265 Daniel M. German Department of Computer Science University of Victoria 1 SEng 265 dmgerman@uvic.ca C implements call-by-value parameter passing int a =
More informationC Language Part 1 Digital Computer Concept and Practice Copyright 2012 by Jaejin Lee
C Language Part 1 (Minor modifications by the instructor) References C for Python Programmers, by Carl Burch, 2011. http://www.toves.org/books/cpy/ The C Programming Language. 2nd ed., Kernighan, Brian,
More informationIntroduction to Scientific Computing and Problem Solving
Introduction to Scientific Computing and Problem Solving Lecture #22 Pointers CS4 - Introduction to Scientific Computing and Problem Solving 2010-22.0 Announcements HW8 due tomorrow at 2:30pm What s left:
More informationIntroduction to C. Systems Programming Concepts
Introduction to C Systems Programming Concepts Introduction to C A simple C Program Variable Declarations printf ( ) Compiling and Running a C Program Sizeof Program #include What is True in C? if example
More informationBSM540 Basics of C Language
BSM540 Basics of C Language Chapter 4: Character strings & formatted I/O Prof. Manar Mohaisen Department of EEC Engineering Review of the Precedent Lecture To explain the input/output functions printf()
More informationFundamentals of Programming Session 7
Fundamentals of Programming Session 7 Instructor: Reza Entezari-Maleki Email: entezari@ce.sharif.edu 1 Fall 2014 These slides have been created using Deitel s slides Sharif University of Technology Outlines
More informationLecture 05 I/O statements Printf, Scanf Simple statements, Compound statements
Programming, Data Structures and Algorithms Prof. Shankar Balachandran Department of Computer Science and Engineering Indian Institute of Technology, Madras Lecture 05 I/O statements Printf, Scanf Simple
More informationDeclaration. Fundamental Data Types. Modifying the Basic Types. Basic Data Types. All variables must be declared before being used.
Declaration Fundamental Data Types All variables must be declared before being used. Tells compiler to set aside an appropriate amount of space in memory to hold a value. Enables the compiler to perform
More informationWhy Pointers. Pointers. Pointer Declaration. Two Pointer Operators. What Are Pointers? Memory address POINTERVariable Contents ...
Why Pointers Pointers They provide the means by which functions can modify arguments in the calling function. They support dynamic memory allocation. They provide support for dynamic data structures, such
More informationLab 3. Pointers Programming Lab (Using C) XU Silei
Lab 3. Pointers Programming Lab (Using C) XU Silei slxu@cse.cuhk.edu.hk Outline What is Pointer Memory Address & Pointers How to use Pointers Pointers Assignments Call-by-Value & Call-by-Address Functions
More informationPointers. 10/5/07 Pointers 1
Pointers 10/5/07 Pointers 1 10/5/07 Pointers 2 Variables Essentially, the computer's memory is made up of bytes. Each byte has an address, associated with it. 10/5/07 Pointers 3 Variable For example 1:#include
More informationLecture 16. Daily Puzzle. Functions II they re back and they re not happy. If it is raining at midnight - will we have sunny weather in 72 hours?
Lecture 16 Functions II they re back and they re not happy Daily Puzzle If it is raining at midnight - will we have sunny weather in 72 hours? function prototypes For the sake of logical clarity, the main()
More informationChapter 3 Structured Program Development in C Part II
Chapter 3 Structured Program Development in C Part II C How to Program, 8/e, GE 2016 Pearson Education, Ltd. All rights reserved. 1 3.7 The while Iteration Statement An iteration statement (also called
More informationArrays in C. Prof. Indranil Sen Gupta Dept. of Computer Science & Engg. Indian Institute of Technology Kharagpur. Basic Concept
Arrays in C Prof. Indranil Sen Gupta Dept. of Computer Science & Engg. Indian Institute of Technology Kharagpur 1 Basic Concept Many applications require multiple data items that have common characteristics.
More informationCC112 Structured Programming
Arab Academy for Science and Technology and Maritime Transport College of Engineering and Technology Computer Engineering Department CC112 Structured Programming Lecture 3 1 LECTURE 3 Input / output operations
More informationAMCAT Automata Coding Sample Questions And Answers
1) Find the syntax error in the below code without modifying the logic. #include int main() float x = 1.1; switch (x) case 1: printf( Choice is 1 ); default: printf( Invalid choice ); return
More informationPhysics 306 Computing Lab 5: A Little Bit of This, A Little Bit of That
Physics 306 Computing Lab 5: A Little Bit of This, A Little Bit of That 1. Introduction You have seen situations in which the way numbers are stored in a computer affects a program. For example, in the
More informationB.V. Patel Institute of Business Management, Computer & Information Technology, Uka Tarsadia University
Unit 1 Programming Language and Overview of C 1. State whether the following statements are true or false. a. Every line in a C program should end with a semicolon. b. In C language lowercase letters are
More informationSir Syed University of Engineering and Technology. Computer Programming & Problem Solving ( CPPS ) Pointers. Chapter No 7
Computer Programming & Problem Solving ( CPPS ) Chapter No 7 Sir Syed University of Engineering & Technology Computer Engineering Department University Road, Karachi-75300, PAKISTAN Muzammil Ahmad Khan
More informationWeek 3 More Formatted Input/Output; Arithmetic and Assignment Operators
Week 3 More Formatted Input/Output; Arithmetic and Assignment Operators Formatted Input and Output The printf function The scanf function Arithmetic and Assignment Operators Simple Assignment Side Effect
More informationIn Fig. 3.5 and Fig. 3.7, we include some completely blank lines in the pseudocode for readability. programs into their various phases.
Formulating Algorithms with Top-Down, Stepwise Refinement Case Study 2: Sentinel-Controlled Repetition In Fig. 3.5 and Fig. 3.7, we include some completely blank lines in the pseudocode for readability.
More informationBinary Representation. Decimal Representation. Hexadecimal Representation. Binary to Hexadecimal
Decimal Representation Binary Representation Can interpret decimal number 4705 as: 4 10 3 + 7 10 2 + 0 10 1 + 5 10 0 The base or radix is 10 Digits 0 9 Place values: 1000 100 10 1 10 3 10 2 10 1 10 0 Write
More informationDecimal Representation
Decimal Representation Can interpret decimal number 4705 as: 4 10 3 + 7 10 2 + 0 10 1 + 5 10 0 The base or radix is 10 Digits 0 9 Place values: 1000 100 10 1 10 3 10 2 10 1 10 0 Write number as 4705 10
More information[0569] p 0318 garbage
A Pointer is a variable which contains the address of another variable. Declaration syntax: Pointer_type *pointer_name; This declaration will create a pointer of the pointer_name which will point to the
More information2) Some coders debug their programs by placing comment symbols on some codes instead of deleting it. How does this aid in debugging?
C Interview Questions and Answers 1) How do you construct an increment statement or decrement statement in C? Answer:There are actually two ways you can do this. One is to use the increment operator ++
More informationESC101N Fundamentals of Computing
ESC101N Fundamentals of Computing Arnab Bhattacharya arnabb@iitk.ac.in Indian Institute of Technology, Kanpur http://www.iitk.ac.in/esc101/ 1 st semester, 2010-11 Tue, Wed, Fri 0800-0900 at L7 Arnab Bhattacharya
More informationArrays and Pointers (part 1)
Arrays and Pointers (part 1) CSE 2031 Fall 2012 Arrays Grouping of data of the same type. Loops commonly used for manipulation. Programmers set array sizes explicitly. Arrays: Example Syntax type name[size];
More informationby Pearson Education, Inc. All Rights Reserved.
Let s improve the bubble sort program of Fig. 6.15 to use two functions bubblesort and swap. Function bubblesort sorts the array. It calls function swap (line 51) to exchange the array elements array[j]
More informationprintf( Please enter another number: ); scanf( %d, &num2);
CIT 593 Intro to Computer Systems Lecture #13 (11/1/12) Now that we've looked at how an assembly language program runs on a computer, we're ready to move up a level and start working with more powerful
More informationChapter 2, Part I Introduction to C Programming
Chapter 2, Part I Introduction to C Programming C How to Program, 8/e, GE 2016 Pearson Education, Ltd. All rights reserved. 1 2016 Pearson Education, Ltd. All rights reserved. 2 2016 Pearson Education,
More informationZheng-Liang Lu Java Programming 45 / 79
1 class Lecture2 { 2 3 "Elementray Programming" 4 5 } 6 7 / References 8 [1] Ch. 2 in YDL 9 [2] Ch. 2 and 3 in Sharan 10 [3] Ch. 2 in HS 11 / Zheng-Liang Lu Java Programming 45 / 79 Example Given a radius
More informationPointers. Part VI. 1) Introduction. 2) Declaring Pointer Variables. 3) Using Pointers. 4) Pointer Arithmetic. 5) Pointers and Arrays
EE105: Software Engineering II Part 6 Pointers page 1 of 19 Part VI Pointers 1) Introduction 2) Declaring Pointer Variables 3) Using Pointers 4) Pointer Arithmetic 5) Pointers and Arrays 6) Pointers and
More informationCAAM 420 FALL 2012 Lecture 9. Mishael Owoyemi
CAAM 420 FALL 2012 Lecture 9 Mishael Owoyemi September 21, 2012 Table of Contents 1 Variables 3 1.1 Recap and Introduction.................................. 3 1.1.1 Recap........................................
More informationCOSC 243. Data Representation 3. Lecture 3 - Data Representation 3 1. COSC 243 (Computer Architecture)
COSC 243 Data Representation 3 Lecture 3 - Data Representation 3 1 Data Representation Test Material Lectures 1, 2, and 3 Tutorials 1b, 2a, and 2b During Tutorial a Next Week 12 th and 13 th March If you
More informationEM108 Software Development for Engineers
EE108 Section 6 Pointers page 1 of 20 EM108 Software Development for Engineers Section 6 - Pointers 1) Introduction 2) Declaring Pointer Variables 3) Using Pointers 4) Pointer Arithmetic 5) Pointers and
More informationPractice question Answers
Practice question Answers COMP-322, Winter 2012, All Sections These questions are not necessarily the same as a final as they aren t necessarily exactly representative of the degree of difficulty, length,
More informationSlides adopted from T. Ferguson Spring 2016
CSE3 Introduction to Programming for Science & Engineering Students Mostafa Parchami, Ph.D. Dept. of Comp. Science and Eng., Univ. of Texas at Arlington, USA Slides adopted from T. Ferguson Spring 06 Pointers
More informationLecture 04 Introduction to pointers
Lecture 04 Introduction to pointers A pointer is an address in the memory. One of the unique advantages of using C is that it provides direct access to a memory location through its address. A variable
More informationPhysics 2660: Fundamentals of Scientific Computing. Lecture 7 Instructor: Prof. Chris Neu
Physics 2660: Fundamentals of Scientific Computing Lecture 7 Instructor: Prof. Chris Neu (chris.neu@virginia.edu) Reminder HW06 due Thursday 15 March electronically by noon HW grades are starting to appear!
More informationSlide Set 2. for ENCM 335 in Fall Steve Norman, PhD, PEng
Slide Set 2 for ENCM 335 in Fall 2018 Steve Norman, PhD, PEng Electrical & Computer Engineering Schulich School of Engineering University of Calgary September 2018 ENCM 335 Fall 2018 Slide Set 2 slide
More informationPointers (part 1) What are pointers? EECS We have seen pointers before. scanf( %f, &inches );! 25 September 2017
Pointers (part 1) EECS 2031 25 September 2017 1 What are pointers? We have seen pointers before. scanf( %f, &inches );! 2 1 Example char c; c = getchar(); printf( %c, c); char c; char *p; c = getchar();
More informationCS 137 Part 8. Merge Sort, Quick Sort, Binary Search. November 20th, 2017
CS 137 Part 8 Merge Sort, Quick Sort, Binary Search November 20th, 2017 This Week We re going to see two more complicated sorting algorithms that will be our first introduction to O(n log n) sorting algorithms.
More informationC How to Program, 6/e by Pearson Education, Inc. All Rights Reserved.
C How to Program, 6/e 1992-2010 by Pearson Education, Inc. An important part of the solution to any problem is the presentation of the results. In this chapter, we discuss in depth the formatting features
More informationUNIVERSITY OF WINDSOR Fall 2007 QUIZ # 2 Solution. Examiner : Ritu Chaturvedi Dated :November 27th, Student Name: Student Number:
UNIVERSITY OF WINDSOR 60-106-01 Fall 2007 QUIZ # 2 Solution Examiner : Ritu Chaturvedi Dated :November 27th, 2007. Student Name: Student Number: INSTRUCTIONS (Please Read Carefully) No calculators allowed.
More information1.3b Type Conversion
1.3b Type Conversion Type Conversion When we write expressions involved data that involves two different data types, such as multiplying an integer and floating point number, we need to perform a type
More informationArrays. CS10001: Programming & Data Structures. Pallab Dasgupta Dept. of Computer Sc. & Engg., Indian Institute of Technology Kharagpur
Arrays CS10001: Programming & Data Structures Pallab Dasgupta Dept. of Computer Sc. & Engg., Indian Institute of Technology Kharagpur Array Many applications require multiple data items that have common
More informationFundamentals of Programming
Fundamentals of Programming Lecture 3 - Constants, Variables, Data Types, And Operations Lecturer : Ebrahim Jahandar Borrowed from lecturer notes by Omid Jafarinezhad Outline C Program Data types Variables
More informationPointer Basics. Lecture 13 COP 3014 Spring March 28, 2018
Pointer Basics Lecture 13 COP 3014 Spring 2018 March 28, 2018 What is a Pointer? A pointer is a variable that stores a memory address. Pointers are used to store the addresses of other variables or memory
More informationC: Pointers. C: Pointers. Department of Computer Science College of Engineering Boise State University. September 11, /21
Department of Computer Science College of Engineering Boise State University September 11, 2017 1/21 Pointers A pointer is a variable that stores the address of another variable. Pointers are similar to
More informationCSE 220: Systems Programming
CSE 220: Systems Programming Pointers and Data Representation Ethan Blanton Department of Computer Science and Engineering University at Buffalo More on void Pointers Void pointers are powerful for raw
More informationArrays and Pointers. CSE 2031 Fall November 11, 2013
Arrays and Pointers CSE 2031 Fall 2013 November 11, 2013 1 Arrays l Grouping of data of the same type. l Loops commonly used for manipulation. l Programmers set array sizes explicitly. 2 Arrays: Example
More informationC How to Program, 7/e by Pearson Education, Inc. All Rights Reserved.
C How to Program, 7/e This chapter serves as an introduction to data structures. Arrays are data structures consisting of related data items of the same type. In Chapter 10, we discuss C s notion of
More informationChapter 1 & 2 Introduction to C Language
1 Chapter 1 & 2 Introduction to C Language Copyright 2007 by Deitel & Associates, Inc. and Pearson Education Inc. All Rights Reserved. Chapter 1 & 2 - Introduction to C Language 2 Outline 1.1 The History
More informationFeatures of C. Portable Procedural / Modular Structured Language Statically typed Middle level language
1 History C is a general-purpose, high-level language that was originally developed by Dennis M. Ritchie to develop the UNIX operating system at Bell Labs. C was originally first implemented on the DEC
More informationPointers and Structure. Bin Li Assistant Professor Dept. of Electrical, Computer and Biomedical Engineering University of Rhode Island
Pointers and Structure Bin Li Assistant Professor Dept. of Electrical, Computer and Biomedical Engineering University of Rhode Island 1 Pointer Variables Each variable in a C program occupies space in
More informationCS2351 Data Structures. Lecture 7: A Brief Review of Pointers in C
CS2351 Data Structures Lecture 7: A Brief Review of Pointers in C 1 About this lecture Pointer is a useful object that allows us to access different places in our memory We will review the basic use of
More informationApplied C and C++ Programming
Applied C and C++ Programming Alice E. Fischer David W. Eggert University of New Haven Michael J. Fischer Yale University August 2018 Copyright c 2018 by Alice E. Fischer, David W. Eggert, and Michael
More informationFundamental of Programming (C)
Borrowed from lecturer notes by Omid Jafarinezhad Fundamental of Programming (C) Lecturer: Vahid Khodabakhshi Lecture 3 Constants, Variables, Data Types, And Operations Department of Computer Engineering
More informationArrays and Pointers (part 1)
Arrays and Pointers (part 1) CSE 2031 Fall 2010 17 October 2010 1 Arrays Grouping of data of the same type. Loops commonly used for manipulation. Programmers set array sizes explicitly. 2 1 Arrays: Example
More informationC Concepts - I/O. Lecture 19 COP 3014 Fall November 29, 2017
C Concepts - I/O Lecture 19 COP 3014 Fall 2017 November 29, 2017 C vs. C++: Some important differences C has been around since around 1970 (or before) C++ was based on the C language While C is not actually
More informationProgramming in C++ Prof. Partha Pratim Das Department of Computer Science and Engineering Indian Institute of Technology, Kharagpur
Programming in C++ Prof. Partha Pratim Das Department of Computer Science and Engineering Indian Institute of Technology, Kharagpur Lecture 10 Reference and Pointer Welcome to module 7 of programming in
More informationPointers and Arrays 1
Pointers and Arrays 1 Pointers and Arrays When an array is declared, The compiler allocates sufficient amount of storage to contain all the elements of the array in contiguous memory locations The base
More informationCS102: Variables and Expressions
CS102: Variables and Expressions The topic of variables is one of the most important in C or any other high-level programming language. We will start with a simple example: int x; printf("the value of
More informationPointers. Mr. Ovass Shafi (Assistant Professor) Department of Computer Applications
Pointers Introduction: A variable is a named memory location that holds some value. Each variable has some address associated with it. Till now we only worked on the values stored in the variables and
More informationSchool of Science and Technology
INTRODUCTION Pointers Unit 9 In the previous unit 8 we have studied about C structure and their declarations, definitions, initializations. Also we have taught importance of C structures and their applications.
More informationGuide for The C Programming Language Chapter 1. Q1. Explain the structure of a C program Answer: Structure of the C program is shown below:
Q1. Explain the structure of a C program Structure of the C program is shown below: Preprocessor Directives Global Declarations Int main (void) Local Declarations Statements Other functions as required
More informationLecture 9. Assignment. Logical Operations. Logical Operations - Motivation 2/8/18
Assignment Lecture 9 Logical Operations Formatted Print Printf Increment and decrement Read through 3.9, 3.10 Read 4.1. 4.2, 4.3 Go through checkpoint exercise 4.1 Logical Operations - Motivation Logical
More informationArrays and Pointers. Arrays. Arrays: Example. Arrays: Definition and Access. Arrays Stored in Memory. Initialization. EECS 2031 Fall 2014.
Arrays Arrays and Pointers l Grouping of data of the same type. l Loops commonly used for manipulation. l Programmers set array sizes explicitly. EECS 2031 Fall 2014 November 11, 2013 1 2 Arrays: Example
More informationFunction I/O. Function Input and Output. Input through actual parameters. Output through return value. Input/Output through side effects
Function Input and Output Input through actual parameters Output through return value Only one value can be returned Input/Output through side effects printf scanf 2 tj Function Input and Output int main(void){
More informationFunction I/O. Last Updated 10/30/18
Last Updated 10/30/18 Program Structure Includes Function Declarations void main(void){ foo = fun1(a, b); fun2(2, c); if(fun1(c, d)) { } } Function 1 Definition Function 2 Definition 2 tj Function Input
More informationTechnical Questions. Q 1) What are the key features in C programming language?
Technical Questions Q 1) What are the key features in C programming language? Portability Platform independent language. Modularity Possibility to break down large programs into small modules. Flexibility
More informationProgramming and Data Structures
Programming and Data Structures Teacher: Sudeshna Sarkar sudeshna@cse.iitkgp.ernet.in Department of Computer Science and Engineering Indian Institute of Technology Kharagpur #include int main()
More informationC LANGUAGE AND ITS DIFFERENT TYPES OF FUNCTIONS
C LANGUAGE AND ITS DIFFERENT TYPES OF FUNCTIONS Manish Dronacharya College Of Engineering, Maharishi Dayanand University, Gurgaon, Haryana, India III. Abstract- C Language History: The C programming language
More informationIntermediate Programming, Spring 2017*
600.120 Intermediate Programming, Spring 2017* Misha Kazhdan *Much of the code in these examples is not commented because it would otherwise not fit on the slides. This is bad coding practice in general
More informationC BOOTCAMP DAY 2. CS3600, Northeastern University. Alan Mislove. Slides adapted from Anandha Gopalan s CS132 course at Univ.
C BOOTCAMP DAY 2 CS3600, Northeastern University Slides adapted from Anandha Gopalan s CS132 course at Univ. of Pittsburgh Pointers 2 Pointers Pointers are an address in memory Includes variable addresses,
More informationOperators in C. Staff Incharge: S.Sasirekha
Operators in C Staff Incharge: S.Sasirekha Operators An operator is a symbol which helps the user to command the computer to do a certain mathematical or logical manipulations. Operators are used in C
More informationOther C materials before pointer Common library functions [Appendix of K&R] 2D array, string manipulations. <stdlib.
1 The previous lecture Other C materials before pointer Common library functions [Appendix of K&R] 2D array, string manipulations Pointer basics 1 Common library functions [Appendix of K+R]
More informationPointers. Introduction
Pointers Spring Semester 2007 Programming and Data Structure 1 Introduction A pointer is a variable that represents the location (rather than the value) of a data item. They have a number of useful applications.
More informationFundamentals of C Programming
Introduction, Constants, variables, keywords, Comments, I/O Functions, Data types, Compilation & Execution Tejalal Choudhary tejalal.choudhary@gmail.com, tejalal.choudhary@sdbct.ac.in Department of Computer
More informationReference operator (&)
Pointers Each cell can be easily located in the memory because it has a unique address and all the memory cells follow a successive pattern. For example, if we are looking for cell 1776 we know that it
More informationPersonal SE. Computer Memory Addresses C Pointers
Personal SE Computer Memory Addresses C Pointers Computer Memory Organization Memory is a bucket of bytes. Computer Memory Organization Memory is a bucket of bytes. Each byte is 8 bits wide. Computer Memory
More informationChapter 2 THE STRUCTURE OF C LANGUAGE
Lecture # 5 Chapter 2 THE STRUCTURE OF C LANGUAGE 1 Compiled by SIA CHEE KIONG DEPARTMENT OF MATERIAL AND DESIGN ENGINEERING FACULTY OF MECHANICAL AND MANUFACTURING ENGINEERING Contents Introduction to
More informationNumber of decimal places of precision has reduced! We supplied a value correct to 12 decimal places
Number of decimal places of precision has reduced! We supplied a value correct to 12 decimal places The output is correct only to 6 decimal places, and the sixth digit is wrong. How did this happen? CKR
More informationPOINTERS - Pointer is a variable that holds a memory address of another variable of same type. - It supports dynamic allocation routines. - It can improve the efficiency of certain routines. C++ Memory
More informationOperators & Expressions
Operators & Expressions Operator An operator is a symbol used to indicate a specific operation on variables in a program. Example : symbol + is an add operator that adds two data items called operands.
More informationBSM540 Basics of C Language
BSM540 Basics of C Language Chapter 3: Data and C Prof. Manar Mohaisen Department of EEC Engineering Review of the Precedent Lecture Explained the structure of a simple C program Introduced comments in
More information