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

int main (int argc, char *argv[]) 
{
  double h;
  double estimate;
  double sum2;
  double wtime;
  double x;
  int i, n;
  int nthreads, tid;
  int procs;
  
  n = atoi(argv[1]);
  h = 1.0 / ( double ) ( 2 * n );
  printf("h = %lf n = %d\n",h,n);
  sum2 = 0.0;

/* Fork a team of threads giving them their own copies of variables */
   procs = omp_get_num_procs();
   omp_set_num_threads(procs);  
   wtime = omp_get_wtime ( );
#pragma omp parallel private( i, x ) shared( h, n ) 
{
#pragma omp for
  for ( i = 1; i <= n; i++ )
  {
    x = h * ( double ) ( 2 * i - 1 );
#pragma omp critical
    sum2 = sum2 + 1.0 / ( 1.0 + x * x );
  }
}
  wtime = omp_get_wtime ( ) - wtime;
  estimate = 4.0 * sum2 / ( double ) ( n );
  printf("The estimate of pi is %15.10f\n",estimate);
  printf ( "  The time is %15.10f\n", wtime );

  return (0);

}