Quick Reference to C Programs

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Introduction
C is a remarkable language. Designed originally by Dennis Ritchie, working at AT&T Bell Laboratories in New Jersey, it has increased in use until now it may well be one of the most widely-written computer languages in the world. C is a structured language. It allows variety of programs in small modules. It is easy for debugging, testing, and maintenance if a language is a structured one.
1.2 Structure of a C program:
Include header file section Global declaration section Main() { Declaration part Executable part } User-defined functions { Statements } Include header file section: C program depends upon some header files for function definition that are used in program. Each header file by default is extended with .h. The header file should be included using # include directive as given here. Global declaration: This section declares some variables that are used in more than one function. These variables are known as global variables. This section must be declared outside of all the functions. Function main: Every program written in C language must contain main () function. The function main() is a starting point of every C program. The execution of the program always begins with the function main (). Declaration part: The declaration part declares the entire variables that are used in executable part. The initializations of variables are also done in this section. Initialization means providing initial value to the variables Executable part: This part contains the statements following the declaration of the variables. This part contains a set of statements or a single statement. These statements are enclosed between the braces.