C Program to Find Area of Square using Macro

This is a simple demonstration of a Macro in C language. This is program is written using Turbo C++ Compiler installed on a Windows XP 64-bit system. You can compile and run this program using an standard C compiler.

This program is intended for intermediate level learners who know how to write a complex C program.

Problem Definition

The program to compute the area of a square use a C macro called ” area (r) r * r “ where r is a parameter which can be replaced with any variable.

Macro code gets replaced directly where they appear within the program and then executed as regular C tokens.

The are declared and defined at the beginning of a C program using #define keyword.

The area(r) receives a variable value called “Length_of_Side” for a square and computes the area of a square.

Program Code

/* Program to find area of square using Macro in c */

#include <stdio.h>

#include <stdlib.h>

#define area(r) (r * r)

main()
{

    int length_of_side;
    int area_of_square;

/* Read the Length of Side of a Square */

    printf("Enter the length of side in 'cm' of a Square:");
    scanf("%d",&length_of_side);

/* Calling Macro area(r) where r is length_of_side */

    area_of_square = area(length_of_side);

    printf("Area of Square = %d",area_of_square);
    printf("cm(square)");

    getch();
    return 0;

}

The program receives the “length of side” in following code.

scanf("%d", &length_of_side);

The length of side is an integer data type.

The area of square is computed using following macro.

area of square = area(lenght_of_side);

It is quickly replaced with r * r and area of square is computed.

Output

Enter the length of side in 'cm' of a square:12
Area of Square = 144cm(square)