// Horstman and Budd page 142 Buffon's Needle Simulation
// Improved by RJBotting
//      Calculate PI rather than use a hard to memorize value
//      Simplify calculating yhigh
//      Factor out 1.0/RAND_MAX

#include <iostream>
#include <cstdlib>
#include <cmath>
#include <ctime>

using namespace std;

int main()
{  /* set seed of random number generator */
   srand(time(0));
   const double SCALE = 1.0/RAND_MAX;

   int NTRIES = 10000;
   const double PI = 4*atan(1); // From Dr. Keith Schubert

   int hits = 0;
   for (int i = 1; i <= NTRIES; i++)
   {  
      double ylow = 2 * (rand() * SCALE);
      double yhigh = ylow + sin( (rand() * SCALE) * PI );
      if (yhigh >= 2) hits++;                      
   }
   cout << "Tries / Hits = " 
      << NTRIES * (1.0 / hits) << "\n";
   return 0;
}