Structure of a C Program

A ‘C’ program consists of the following sections.

1. Documentation Section
2. Linkage Section
3. Constant Definition Section
4. Global Variable Declaration Section
5. Main( ) Function Section

{

i) Declaration Section

ii) Executable Section

}

1. Sub Program Section.

Documentation Section : This section is used for giving comments on the program.

Syntax : /* . . . Comments . . . */

Linkage Section : This section is used to make reference to header file.

Syntax : #include<Header file name>

Constant Definition Section : This section is used to define constants for the program.

Syntax : #define Constant name Value

Global Variable Declaration Section : This section is used to declare variables that can be shared among different functions within the program.

Syntax : Storage class Data type Variable List

Main ( ) Function Section : Every ‘C’ program will definitely have this section. This section contains two sub sections.

i) Declaration Section : This section contains local declarations for main( ) functin.

Syntax : Storage Class Data Type Variable List

ii) Executable Section : This section contains actual executable instructions for the program.

Sub Program Section : This section contains one or more user defined functions.

EXAMPLE PROGRAM:

Write a Program for preparing bills of a shop.

/* Program for Preparing Bill of a Shop*/ Documentation Section

#include<stdio.h> Linkage Section

main( ) Main( ) Function Section

{

int itemno , qty ;

float uprice , bill=0.00 ; Declaration Section

char itemname[20] ;

printf(“Enter Item No : ”);

scanf(“%d”, &itemno );

printf(“Enter Item Name : “) ;

scanf(“%s”, itemname);

printf(“Enter Quantity Taken : “); Executable Section

scanf(“%d”, &qty);

printf(“Enter Unit Price : “) ;

scanf(“%f”, &uprice) ;

bill = uprice * qty ;

printf(“Total Bill = %.2f” , bill) ;

}