How to find volume of cylinder?

CODE

How to find volume of cylinder?

//Write a program to find volume of cylinder using pointer..

int main()

{

    float r,h,v,*pr,*ph,*pv;

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

    scanf("%f%f",&r,&h);

    pr=&r;

    ph=&h;

    pv=&v;

    *(pv)=3.14*(*pr)*(*pr)*(*ph);

    printf("\n volume of cylinder=%f",v);

}

Output:

enter radius and height :

4

7

 volume of cylinder=351.679993