C program to find the area and circumference of the circle with radius 'r'

#include<stdio.h>
#include<conio.h>
void main()
{
float r,a,c;
puts("Enter the radius of the circle");
scanf("%f",&r);
a=(r*r*22)/7;
c=(2*r*22)/7;
printf("Area of the circle = %f\n",a);
printf("Circumference of the circle = %f\n",c);
}