Circumference of Circle Example in C

About this program

This is an example program in c calculation programs. Read the concept first: Data Types in C Programming, then study the code and output below.

Definition

When a circle’s diameter is 1, its circumference is π. When a circle’s radius is 1—called a unit circle—its circumference is 2π.

Formula

The circumference of a circle is written

π = C / d

Or, equivalently, as the ratio of the circumference to twice the radius. The above formula can be rearranged to solve for the circumference:

C = π * d = 2π * r

here,

r = Radius
π = ~3.14

Circumference Of Circle Example Program

/*##Circumference Of Circle*/
/*##Calculation Programs, Datatype Programs, Basic Programs*/

#include<stdio.h>

float PI = 3.14;

int main(){
   float radius, ci;

   printf("\nEnter the radius of Circle : ");
   scanf("%f", &radius);

   ci = 2 * PI * radius;
   
   printf("\nCircumference of Circle : %f", ci);

   return (0);
}

Sample Output

Enter the radius of Circle : 2

Circumference of Circle : 12.560000

Related Pages

Learn the concept first, then study the code:

• C Programs — Browse all C Programs.
• Data Types in C Programming — Concept — int, float, double and format specifiers.
• Area Of Circle Example C Program — More in c calculation programs.
• Area Of Square Example C Program — More in c calculation programs.