#include <stdio.h>#define NUM_STEPS 1000000double step, pi;void main(){  int i;	   double x, sum = 0.0;   step = 1.0/(double) NUM_STEPS;   for (i=0; i< NUM_STEPS; i++){      x = (i+0.5)*step;      sum = sum + 4.0/(1.0 + x*x);   }   pi = step * sum;   printf("Pi = %12.9f\n",pi);}