# C Programming code to calculate area of a circle

C Programming code to calculate area of a circle by defining pi as 3.1415

**Algorithm**

- Define pi as 3.1415 since pi is not a predefined constant in C
- Accept the radius of the circle
- Calculate the area of the circle
- Display the output

**Code**

`#include<stdio.h>`

#include<conio.h>

#define pi 3.1415

void main()

{

clrscr();

int r;

float a;

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

scanf("%d",&r);

a=pi*r*r;

printf("\n Radius= %d",r);

printf(" \n Area= %f",a);

getch();

}