C Program To Find Area And Perimeter of Rectangle

A rectangle has two important measurements: area, which represents the space enclosed by it, and perimeter, which represents the total length of its boundary.

• The area of a rectangle is calculated as length × width.
• The perimeter is calculated as 2 × (length + width).

Example

Input:

l = 10
b = 10

Output: 

area = 100
perimeter = 40

Explanation: 

The formula for the area of a rectangle is 

Area = length*breadth => l*b

The formula for the perimeter of a rectangle is 

Perimeter = 2*(length + breadth) => 2*(l+b)

Method 1: Direct Calculation

The area and perimeter are calculated directly inside the printf() statements.

#include <stdio.h>

int main()
{

    int l = 10, b = 10;
    printf("Area of rectangle is : %d", l * b);
    printf("\nPerimeter of rectangle is : %d", 2 * (l + b));
    return 0;
}

Area of rectangle is : 100
Perimeter of rectangle is : 40

Method 2: Using Variables

Separate variables are used to store the calculated area and perimeter before displaying them.

#include <stdio.h>

int main()
{

    int l = 10, b = 10;
    int A, P;
    A = l * b;
    P = 2 * (l + b);
    printf("Area of rectangle is : %d", A);
    printf("\nPerimeter of rectangle is : %d", P);
    return 0;
}

Area of rectangle is : 100
Perimeter of rectangle is : 40

Method 3: Using functions 

We can also calculate the area and perimeter using separate functions. This makes the program more modular and reusable.

#include <stdio.h>

int area(int a, int b)
{
    int A;
    A = a * b;
    return A;
}
int perimeter(int a, int b)
{
    int P;
    P = 2 * (a + b);
    return P;
}

int main()
{

    int l = 10, b = 10;
    printf("Area of rectangle is : %d", area(l, b));
    printf("\nPerimeter of rectangle is : %d",
           perimeter(l, b));
    return 0;
}