Structure of a C Program
To find out the structure of a C program, consider following
Example
#include<stdio.h>
int main()
{
int sum;
printf("Hello World, sum is : ");
sum=sum1(2,2);
printf("%d",sum);
getchar();
return 0;
}
int sum1(int x, int y)
{
return x+y;
}
Any C program generally having structure as :-
- Include Header Files
- Define Global Variables
- Define main Function
- Execute Statements, Call Other Functions
- Define Other Functions
If we consider the above program, then above lines are explained as :
| Line Number | Explanation |
|---|---|
| 1st | We have include header files which are necessary for inclusion because of printf() and other standard input output functions. |
| 2nd | To define main() function, it’s the first function that compiler executes and also the starting of out program because this functions is executed at first. Other statements are executed later on. |
| 3rd | Opening Curly Brace for starting main() function block. |
| 4th | A variable (sum) of type Integer is defined. |
| 5th | printf() is a standard function that is used to output data to the console output(computer screen). |
| 6th | integer sum is assigned value of 2 variables by calling the function sum1 with parameters 2,2 |
| 7th | to output sum to computer screen. |
| 8th | getchar() is a function which is used to stop computer screen after outputting a value, because if we don’t put it the screen disappear after output of text, so getchar() will wait to type a character from keyboard until output window will not be disappeared |
| 9th | A return code 0 is returned by function to the Operating system. So that the operating system knows that program executed successfully. (not necessary) |
| 10th | main function closed |
| 12th | sum1() function is defined with two temporary parameters. |
| 14th | sum of x and y is returned |
