C program to find area and circumference of circle when radius is given.

#include<stdio.h>
#include<conio.h>
#include<math.h>
//define pi 3.14
void main(){
const float pi=3.14;
float r,area,cir;
clrscr();
printf("enter radius of a circle\n");
scanf("%f",&r);
area=pi*r*r;
cir=2*pi*r;
printf("area of circle=%f\n and circumference of circle=%f",area,cir);
getch();
}