/* if we assume pi=area under 4/(1+x^2) from x=0..1 then is this pi? */
#include <stdio.h>
#include <math.h>

main()
{
  double x=0.0;
  double y=0.0;
  double area=0.0;
  double strip=0.0;
  double slice=0.00001;

  long slices;
  long i;

  slices = (long) (1.0/slice);

  x=0.0;
  for(i=0;i<slices;i++) {
	  y = 4.0 / (1.0 + x*x);
	  area += y*slice;
	  x += slice;
  }

  printf("Slices = %ld, approx PI = %lf\n", slices, area);
}