/* calculating PI by Monte Carlo method*/

#include<stdio.h>
#include<stdlib.h>

#define N 100000000

double randf()
{
return((float)(rand())/(float)(RAND_MAX+1.0));
}


main()
{long int Nc, i, j;
 double x, y;
 Nc=0;
 j=0;
 for(i=1; i<=N; i++)
 {j++;
  x=2.0*randf()-1.0;
  y=2.0*randf()-1.0;
  if ((x*x+y*y)<=1.0) Nc++;
  if (j>=10000) {printf("%lf\n",4.0*(double)(Nc)/(double)(i)); j=0;}
 }
 getchar();
}