C programming chapter 1-3

 

                

C programming by UAH TECHTUBE

C programming chapter 1-3

C Language Overview

This chapter describes the basic details about C programming language, how it emerged, 

what are strengths of C and why we should use C.

The C programming language 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 PDP-11 computer in 1972.

In 1978, Brian Kernighan and Dennis Ritchie produced the first publicly available 

description of C, now known as the K&R standard.

The UNIX operating system, the C compiler, and essentially all UNIX applications programs 

have been written in C. The C has now become a widely used professional language for 

various reasons.

 Easy to learn

 Structured language

 It produces efficient programs.

 It can handle low-level activities.

 It can be compiled on a variety of computer platforms.

Facts about C

 C was invented to write an operating system called UNIX.

 C is a successor of B language, which was introduced around 1970.

 The language was formalized in 1988 by the American National Standard Institute.

(ANSI).

 The UNIX OS was totally written in C by 1973.

 Today, C is the most widely used and popular System Programming Language.

 Most of the state-of-the-art softwares have been implemented using C.

 Today's most ][popular Linux OS and RBDMS MySQL have been written in C.

Why to use C?

C was initially used for system development work, in particular the programs that make up 

the operating system. C was adopted as a system development language because it 

produces code that runs nearly as fast as code written in assembly language. Some 

examples of the use of C might be:

 Operating Systems

 Language Compilers

 Assemblers

 Text Editors

 Print Spoolers

 Network Drivers

 Modern Programs

 Databases

 Language Interpreters

 Utilities

C Programs

A C program can vary from 3 lines to millions of lines and it should be written into one or 

more text files with extension ".c"; for example, hello.c. You can use "vi", "vim" or any 

other text editor to write your C program into a file.

This tutorial assumes that you know how to edit a text file and how to write source code

using any programming language.

C Environment Setup

This section describes how to set up your system environment before you start doing your 

programming using C language.

Before you start doing programming using C programming language, you need the following 

two softwares available on your computer, (a) Text Editor and (b) The C Compiler.

Text Editor

This will be used to type your program. Examples of few editors include Windows Notepad, 

OS Edit command, Brief, Epsilon, EMACS, and vim or vi.

Name and version of text editor can vary on different operating systems. For example,

Notepad will be used on Windows, and vim or vi can be used on windows as well as Linux or 

UNIX.

The files you create with your editor are called source files and contain program source 

code. The source files for C programs are typically named with the extension “.c”.

Before starting your programming, make sure you have one text editor in place and you 

have enough experience to write a computer program, save it in a file, compile it and finally 

execute it.

The C Compiler

The source code written in source file is the human readable source for your program. It 

needs to be "compiled", to turn into machine language so that your CPU can actually 

execute the program as per instructions given.

This C programming language compiler will be used to compile your source code into final 

executable program. I assume you have basic knowledge about a programming language 

compiler.

Most frequently used and free available compiler is GNU C/C++ compiler, otherwise you can 

have compilers either from HP or Solaris if you have respective Operating Systems.

Following section guides you on how to install GNU C/C++ compiler on various OS. I'm 

mentioning C/C++ together because GNU gcc compiler works for both C and C++ 

programming languages.

Installation on UNIX/Linux

If you are using Linux or UNIX, then check whether GCC is installed on your system by 

entering the following command from the command line:

$ gcc -v

If you have GNU compiler installed on your machine, then it should print a message 

something as follows:

Using built-in specs.

Target: i386-redhat-linux

Configured with: ../configure --prefix=/usr .......

Thread model: posix

gcc version 4.1.2 20080704 (Red Hat 4.1.2-46)

If GCC is not installed, then you will have to install it yourself using the detailed 

instructions available athttp://gcc.gnu.org/install/

This tutorial has been written based on Linux and all the given examples have been 

compiled on Cent OS flavor of Linux system.

Installation on Mac OS

If you use Mac OS X, the easiest way to obtain GCC is to download the Xcode development 

environment from Apple's web site and follow the simple installation instructions. Once you 

have Xcode setup, you will be able to use GNU compiler for C/C++.

Xcode is currently available at developer.apple.com/technologies/tools/.

Installation on Windows

To install GCC at Windows you need to install MinGW. To install MinGW, go to the MinGW 

homepage, www.mingw.org, and follow the link to the MinGW download page. Download 

the latest version of the MinGW installation program, which should be named MinGW-

<version>.exe.

While installing MinWG, at a minimum, you must install gcc-core, gcc-g++, binutils, and 

the MinGW runtime, but you may wish to install more.

Add the bin subdirectory of your MinGW installation to your PATH environment variable, so 

that you can specify these tools on the command line by their simple names.

When the installation is complete, you will be able to run gcc, g++, ar, ranlib, dlltool, and 

several other GNU tools from the Windows command line.

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