How to find area and circumference of circle using C Programming

C Program to find area and circumference of circle

#include <stdio.h>

int main() {
 
   int rad;
   float PI = 3.14, area, ci;
 
   printf("\nEnter radius of circle: ");
   scanf("%d", &rad);
 
   area = PI * rad * rad;
   printf("\nArea of circle : %f ", area);
 
   ci = 2 * PI * rad;
   printf("\nCircumference : %f ", ci);
 
   return (0);
}

Output :

Enter radius of a circle : 1
Area of circle : 3.14
Circumference : 6.28

Explanation of Program :

In this program we have to calculate the area and circumference of the circle. We have following 2 formulas for finding circumference and area of circle.

Area of Circle = PI * R * R

And

Circumference of Circle = 2 * PI * R

In the above program we have declared the floating point variable PI whose value is defaulted to 3.14.We are accepting the radius from user.

printf("\nEnter radius of circle: ");
scanf("%d", &rad);