An Overview of C/C++ Programming Language and Programming Environment

Transcription

1 1 An Overview of C/C++ Programming Language and Programming Environment 1-1 An Overview of Programming Languages Introduction to Operating Systems MS-DOS and Network Operating System Commands Basic Terms of Software Systems C Programming Examples 1-13

2 P. Lin/ August, An Overview of Programming Languages The structure and operation of a computer - Computer system: Hardware and firmware - Processor (registers, primitive operations) - Main memory (RAM, ROM) - Data items (integers, real or floating-point numbers, strings, etc.) - Sequence and data control - Storage management - Operating environment Major influences on the evolution of programming language 1. Computer hardware and operating systems 2. Applications 3. Programming methods 4. Implementation methods 5. Standardization Programming languages - Assembly language - Machine Language (Machine instructions in binary strings) - ALGOL - FORTRAN (Formula Translator; IBM now) - APL - BASIC (Beginners All-purpose Symbolic Instructional Code) - COBOL (Common Business Oriented Language; 1959) - RPG - Pascal (Professor Nicklaus Wirth, 1971) - PL/I - Lisp (Artificial Intelligence applications) - PROLOG - C language (General purpose programming language; 1972, AT&T) - ADA (Real-time distributed system; Department of Defense; 1980s - now) - C++ language (1999 now) - Java (1995 now) - Visual BASIC.NET (1999 now) - C# (2000s now) Types of Programs - High-Level Language Program - Low-Level Language Program

3 P. Lin/ August, Procedure-Oriented Language - Object-Oriented Language - Event-Driven Programming language (Visual Basic) - Component-based language Some Example of Computer Program Applications - Business systems (data processing) - System programming - Real time and/or embedded systems - Network applications - Scientific and engineering Program Development Process 1. Understand a given problem 2. Requirement specification (make necessary assumptions) 3. Analysis (analyze the problem and accumulate facts 4. Design and refine programs 5. Implementation 6. Verification and Testing A Set of Tools for Programmers Text editor Compiler Library utilities Linker Make utilities Debugger Programmer s Task 1. Coding: translate an algorithm into suitable computer language statements (Editor) 2. Test the resultant program (Compile and build) 3. Debug the program 4. Document the program Program = Algorithm + Data Data Structures - Organization of data for computer processing - Choice of data structure (Arrays, vectors, matrices, tables, etc)

4 P. Lin/ August, Algorithms: Webster dictionary: A procedure for solving a mathematical problem in a finite number of steps that frequently involves repetition of an operation An unambiguous procedure for solving a problem A finite sequence of well defined steps or operations for the solution of a given problem Algorithm analysis (time and/or memory efficiency): - The best case - The worst case - The average case How to express algorithms: 1. Flow chart (lack of control structure; represent a procedure in terms of if() and goto statements) 2. Computer programs (ALGOL) 3. Mathematical algorithms 4. Pseudo code (English-like description of the solution) Example 1-1. Average of N numbers Write an algorithm to read in N numbers, computer and print the average. Step 1: Input N1, N2,.., N numbers Step 2: Compute the sum of N numbers Step 3: Divide sum by N and save the result Step 4: Print the average Criteria for Programming Language Evaluation 1. Data types and structures 2. Modularity 3. Input-output facilities 4. Portability 5. Efficiency 6. Standardization 7. Mix-language programming support

5 P. Lin/ August, Introduction to Operating Systems Operating systems A software system contains many programs for controlling the computer hardware System Resource manager: processor, memory, input/output devices, communication devices, and data Functions: User interface Input/output systems Job and Task management (loading, resource allocation, error termination, communication between jobs and operating systems) File system management (management, allocation, protection, backup, etc.) Data sharing among users Resource sharing and scheduling Real memory management Virtual memory management Networking and communications Other system utilities Network Operating Systems A collection of software and associated protocols that allows a set of interconnected computers to be used together on resource sharing Client-server applications Remote access services Security control Printer management Internet and Intranet services Server and network monitoring Some examples: - Windows XP, Vista - UNIX - Linux Some Examples of Operating Systems CP/M (first operating system for Intel 8085/8086-based microcomputer) DOS (Disk Operating System) 1980; Character oriented UNIX 1970; Character oriented Microsoft Windows 1990; Graphical User Interface (GUI) Digital Equipment Corporation (DEC) VAX/VMS operating system

6 P. Lin/ August, MVS (1974, Multiple virtual storage) and VM (1990, Virtual Machine) of IBM mainframe operating systems UNIX, AIX, Linux Microsoft XP, Vista, Server 2003, Server 2005, Mobile 6.0 Windows Definition: A window is an application written for the Microsoft Windows operating system A rectangular area of the screen where an application displays output and receives input from the user. A window shares the screen with other windows Only one window at a time can receive input from the user The user can use the mouse, keyboard, or other input device to interact with a window and the application that owns it.

7 P. Lin/ August, MS-DOS and Network Operating System Commands Windows/DOS Commands are not case sensitive Windows/DOS commands are available under only MS-DOS console window: Window XP/Vista Start button Command or cmd to inovoke Window cosole or command line window Some commands: Md Mkdir Cd Rmdir Rename Copy Xcopy Del Type Sys Chkdsk Scandisk Fdisk Format Date Time Ver Cls Debug Edit Mem Regedit Uninstall Help Create directory (file folder) Same as Md command Change director Remove director Rename a file Copy a file Copy groups of files or subdirectories for one location to another Delete a file Display content of a file on the screen Copy the system files to a disk to make it bootable disk Display information about the disk; identify and correct errors A utility to identify disk errors and fix them Create disk partitions and sets the boot and active partitions Format a hard disk with sectors and tracks Display current system date and prompt desired new date Display current system time and prompt desired new time Display the version of operating system Clear the monitor screen Invoke the Intel 8086 mini-assembler Invoke Microsoft text-based editor Display info about how system memory is used Window s Registry editor Used to remove Windows 95 form a system that has been upgraded from MS-DOS Helps on DOS commands Some Network Related Net Commands (available only if the PC is connected to a network) Net time Net file Net name Net use Used to synchronize the server s clock Show the currently open share files and file locks Display, add, and remove computer names that can participate in the message service Show information about shared resources

8 P. Lin/ August, Net view Netstat Ping Tracert Show a list of domains, the computers and servers in a domain Display information about the TCP/IP session at the server Poll another TCP/IP node to verify that you can communicate with it Used to view the number of hops, and other routing information, on the path to the specified server or host

9 P. Lin/ August, Basic Terms of Software System ANSI C The standardized C programming language (American National Standard Institute) Program An executable file that usually created by a link editor and resides on a disk file A static sequence of computer instructions System software Software that provide services for the users of the computer system Application software Software that were written for specific tasks Word processor, game programs, spreadsheet Compiler A program that translate a source code program into machine language program Editor A program that is used to enter and/or modify source code program and save it on a disk file Linker A program that combine object files and libraries to produce an executable file Loader A program that place the executable program into appropriate main memory area for execution Run-time library Functions included with a compiler that program can call to perform various basic operations Console The Windows subsystem that runs character-based applications as opposed to applications that have a graphical user interface Kernel Also called core or nucleus

10 P. Lin/ August, A small portion of the most intensively used code that resides in the main memory (RAM/ROM) Some typical service functions provided by a Windows kernel: File system Security system Memory management (virtual memory) Device I/O and network drivers Thread scheduling Message passing Various application program interfaces (APIs), and Networking, etc. File A stream of characters An instance of an opened file or I/O devices Task An executing program in Win16 is known a task Application Programming Interface (API) A set of functions supported by the Windows operating system Dynamic Link Libraries A program module containing functions that other programs or DLLs can call. Not self executable, other programs must load them Non-preemptive Multitasking Operating System An operating system can load and run multiple programs simultaneously One application must tell the operating system that it s finished processing before the operating system can switch to perform another task Preemptive Multitasking Operating System An operating system performs a form of multitasking in which the operating system does not wait for a thread to voluntarily yield the processor to other programs. The operating system interrupts a program after the program has run for a preset amount of time Process

11 P. Lin/ August, An instance of a running program Contains actual code, data, and system resources (semaphores, communication ports, files, etc.) Every process has at least one thread After a thread begins, it can create additional threads Heap Used to allocate data space for a process dynamically when the process is running Windows 95 allows applications to support multiple heaps in the same process Stack Used dynamically while the process is running Stack frames contain the data elements required by a function and return address linkage for each function call System Calls Obtain services from the kernel Thread A entity within a process that the kernel schedules for execution An independent program counter Major components of a thread: A client ID A set of registers holding the state of the processor Two stacks: One for use in the user mode, Another one for use while executing in kernel mode A private storage area for use by subsystems, runtime libraries, and dynamic link libraries (DLL) Virtual Memory Management A memory sharing scheme An operating system distributes the available memory among processes while protecting the code and data of one process from other processes Cache High speed static RAM (random access memory) memory for buffering frequently used data File caching

12 P. Lin/ August, Exceptions Synchronous errors or irregular events that cause the execution of program outside the normal flow of control Rich text Text saved with formatting instructions that multiple applications can read and interpret Unicode A universal character encoding standard for worldwide applications Uses a fixed-width, 16-bit character or double-byte character sets (DBCS)s encoding scheme Unicode supporting examples: Windows NT and Windows 95 wchar_t: 16 or 32-bit wide-character type defined in the ANSI C Visual C++ supports wide characters as data, but not as source file text Callbacks Windows operating systems might not be able to send a reply immediately to client applications that post messages in the thread message queue A client may send a request and then wait for a reply callbacks from the operating system Clipboard Data Transfer Operations A Windows utility used a buffer for copying and pasting text, graphics, and windows OLE (Object Linking and Embedding) style of Drag and Drop A set of standard software services built on top of the OLE Components Object Model (COM) that allows software components from different vendors (possibly written in different programming language) to be combined with another to form complete applications Allows the user to move data among desktop, folders, and other applications

13 P. Lin/ August, C Programming Examples Types of Applications and Environment Console applications (Character-oriented) using ANSI C standard libraries Console applications (Character-oriented) using ANSI C and C++ libraries Console applications (Character-oriented) using ANSIC, C++ libraries and API (Application Program Interface) functions Windows Applications using API functions Windows Applications using MFC (Microsoft Foundation Class) Libraries and API functions Visual Studio: C#, VB.NET, etc Visual C /2008 Express Edition Example 1-1: Create and run the Hello C! program using Visual C Express edition. We will create a New Console Application, Add a Source File, then Build the Application using Visual C express edition. Here we will show you how to create a New Console Application from an Empty Project in Visual C (or 2008) Express Edition 1. Start Visual C++ Express Edition (2005 or 2008) 2. File menu => New => Project, to show the New Project dialog box 3. In the Project types subwindow, click on Win32 4. In the Templates subwindow, click on Win32 Console Application

14 P. Lin/ August, Make a 264F08 folder on your C drive, and use the default Location for housing this new project which is the setup by Visual C or Enter project Name: Demo1; also enter the same name: Hello as the Solution Name, then click OK button (see above New Project screen) 7. In the Win32 Application Wizard, click Next 8. Then Click the box in front of the Empty project (no code will be generated), then click Finish

15 P. Lin/ August, In the Solution Explorer, right click on Source Files, Add => New Items

16 P. Lin/ August, Now, you will add a source file to the project as follows. a. In the Add New Item dialog box, select Code node in the Categories b. Select C++ File (.cpp) c. Enter the file name as Hello.c, then click Add button

17 P. Lin/ August, d. Then enter the following source code right inside the editing window

18 P. Lin/ August, #include <stdio.h> void main(void) { } printf("%s, Hello C!\n"); 11. Now, Build, Test, and Debug the program a. Click Build => Build All (this action, will compile, link, and construct an executable file) b. Click Debug => Start without Debugging c. The result is shown in the following console screen

19 P. Lin/ August, Example 1-2: This program output three lines of text on the console screen. /* output.c */ #include <stdio.h> #include <stdlib.h> void main() { system("cls"); printf("\t\t*********************************************\n"); printf("\t\teet 264 C Programming Lang. With Applications\n"); printf("\t\t*********************************************\n"); printf("\a"); /* beep */ return 0; } Program Output: ********************************************* EET 264 C Programming Lang. With Applications ********************************************* Symbols Meaning output.c The saved program or file name /* Begin program s comment */ End program s comment void Nothing to return to the operating system main()

20 P. Lin/ August, Entry point of a C program A function name Allow only one main() function in a C program { } Begin a function block End a function block # include <stdio.h> printf() ; \ t \ n \ a Preprocessor command for file inclusion The header file defines all standard input and output drivers that is located in the C compiler s include sub-directory Screen output function defined in <stdio.h> End of a statement (a delimiter) Horizontal tab (control character) New line (control character) Audible beep Double quotes for enclosing a ASCII character string

21 P. Lin/ August, Example 1-3: This program displays a title box. /* box.c */ #include <stdio.h> Define string constants Text replacement done by the C preprocessor before compiling the program #define M1 "********************\n" #define M2 "* *\n" void main() { printf(m1); /* printf("********************\n") */ } printf(m2); /* printf("* *\n") */ printf(m2); /* printf("* *\n") */ printf(m1); /* printf("********************\n") */ Program Output: ******************** * * * * ********************

22 P. Lin/ August, Example 1-4: This program uses a simple for loop to repeat the message output process. /* message.c */ Define a symbolic constant #include <stdio.h> #define COUNT 3 void main() { Define an integer variable int i; Check ending condition Initialization Updating for(i = 0; i < COUNT; i++) { Begin for loop printf("welcome to C!\n"); printf("\a"); /* beep */ } } End for loop Program Output: Welcome to C! Welcome to C! Welcome to C! Symbols message.c #define COUNT For Meaning The saved program or file name Preprocessor command for defining a symbolic constant A named constant The for() loop control structure < Less than conditional operator ++ Increment by 1

23 P. Lin/ August, Review Questions 1. List at least three programming languages and their major applications. 2. Name the major steps of the program development process. 3. What is a C program? 4. What are the main functions of an operating system? 5. Distinguish the difference between main memory and secondary storage. 6. List some differences between personal computer operating systems and network operating systems. 7. Give two methods of copy a file from one drive to another with the same name. 8. What is a process? 9. What is a thread? 10. Define each of the following terms: cache, program, file, dynamic link library, virture memory. 11. List three programs that work together in order to execute a C program. 12. Give MS-DOS commands for the following activities: (a) Display the directory of a diskette in the A drive (b) Clear the screen (c) Check the version of the operating system (d) Check the memory utilization of the PC 13. Give a definition of the term algorithm 14. What is the purpose of the main() in a C program? 15. Explain the purpose of a pair of braces surround a C program. 16. Write an algorithm to find the roots of the equation: y = Ax 2 + Bx + C.