1.    The C program essentially consists of header files required for library function used.
2.    Every  C program must have at least a function with the name main().
3.    To use any variable in the program, they must be declared first.
4.    The program can have more than one function.

/* comment about the program */
#include<……..>
……….
……….
/* prototype declaration here */
……….
……….
/* global variable declaration here if any */
……….
……….
void main()
{
/* variable declaration here */
/* statements */
getch();
}
return_type function_name (arg_type arg, …)
{
/* variable declaration here */
/* statement */
……….
……….
return variable_name;
}