C Tutorials

Why use C? C was initially used for system development work, particularly 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 the 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

Facts about C   • C was invented to write an operating    system called UNIX.   • C is a successor of B language which  was introduced around the early 1970s.   • The language was formalized in 1988  by the American National Standard  Institute (ANSI).   • The UNIX OS was totally written in C.   • Today C is the most widely used and  popular System Programming Language.   • Most of the state-of-the-art software  have been implemented using C.   • Today's most popular Linux OS and RDBMS MySQL have been written in C.    

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. Before we study the basic building blocks of the C programming language, let us look at a bare minimum C program structure so that we can take it as a reference in the upcoming chapters.     Syntax/Format of simple C program main ()  <--------------------- Function name  {  <------------------------------ Start of program         ........         ........  <------------------- Program statement         ........  }  <------------------------------ End of program      Hello World Example A C program basically consists of the following parts − • Preprocessor Commands • Functions • Variables • Sta...

         The main Function The main is a part of every C program. C permits diferent forms of main statement. Following forms are allowed. main() int main void main() main(void) void main(void) int main(void) The empty pair of parentheses indicates that the function has no arguments. This may be explicitly indicated by using the keyword void inside the parentheses. We may also specify the keyword int or void before the word main . The keyword void means that the function does not return any information to the operating system and int means that the function retúrns an integer value to the operating system.   When int is specified, the last statement in the program must be "return O" . For the sake of simplicaty, we use the first form in our program. Example:                                  // Programm of Addition       // Writ...