How to write program for volume of cone

CODE

How to write program for volume of cone

//v=3.14*r*r*h/3

int main()

{

    float v,r,h;

    printf("\n enter the radius and height:");

    scanf("%f%f",&r,&h);

    v=3.14*r*r*h/3;

    printf("\n volume=%f",v);

}

Output:

Enter the radius and height:

3

6

 Volume=56.520000