To find the area and the volume of a Sphere by varying the radius

The program

#include<stdio.h>

#include<stdlib.h>

#include<math.h>

int main()

{

int i,j,r,c=0;

float x,y,z,eq,pi,S,V;

printf("-:VOLUME AND SURFACE OF SPHERE:-\n\n\n");

printf("ENTER THE VALUE OF THE RADIUS OF THE SPHERE: ");

scanf("%d",&r);

for (i=1;i<=10000;i++)

{

x=(rand()%(2*r+1)+(-1*r));

y=(rand()%(2*r+1)+(-1*r));

z=(rand()%(2*r+1)+(-1*r));

eq=pow(x,2)+pow(y,2)+pow(z,2);

if (abs(eq)<=pow(r,2))

{

 c=c+1;

}

}

pi=6*c/float(i);

V=4*pi*pow(r,3)/float(3);

S=4*pi*pow(r,2);

printf("Pi IS  %f\n\n\n\n",pi);

printf("VOLUME OF THE SPHERE IS %f\n\n\n\n ",V);

printf("SURFACE AREA OF THE SPHERE IS %f\n\n\n\n ",S);

}