C Program 7: To find the area and perimeter of rectangle and circumference of circle

Aim: The length & breadth of a rectangle and radius of circle are input through the keyboard. Write a program to calculate the area and perimeter of the rectangle, and the circumference of the circle.

Theory: you need to know about three mathematical formulas and here you go.. This is the code..

//to find area and perimeter of rectangle and circumference of circle

#include<stdio.h>

#include<conio.h>

int main()

{

    int l,b,i;

    float r, area, peri, circum;

    printf("Calculating the area and perimeter of rectangle\n");

    printf("Enter the Length and breadth of rectangle: ");

    scanf("%d%d", &l, &b);

    peri= 2*(l+b);

    area= l*b;

    printf("The area of the rectangle is: %f\n", area);

    printf("The perimeter of the rectangle is: %f\n", peri);

    for(i=0; i<80; i++)

    {

             printf("*");

    }

    printf("\n");

    printf("Calculating the radius of circle\n");

    printf("Enter the radius of the circle\n");

    scanf("%f", &r);

    circum=2*3.14*r;

    printf("The cirumference of the circle is: %f", circum);   

    getch();

    return 0;

}

First we calculated the area and perimeter of rectangle using formulae: 

scanf("%d%d", &l, &b);

peri= 2*(l+b);

Then we calculate the circumference of circle using formula: circum=2*3.14*r;

Ignore the for loop used inside the program. That isn't actually required. I just used it to make the output look more organized.

Here's the output: