// Oldham, Jeffrey D.
// 2000 Jan 31
// CS 3352

// Number of Heads Among Coin Tosses

// Command-Line Argument
// 1. number of trials

#include <iostream>
#include <stdlib.h>		// has EXIT_SUCCESS
#include "rng.h"
#include <time.h>		// has time()
#include <unistd.h>		// for getpid()
#include <sys/types.h>		// for getpid()
#include <limits.h>		// has ULONG_MAX


// Equilikely(a,b) returns a random integer in the range a, a+1, ..., b.
template <class LONG>
LONG Equilikely(const LONG & a, const LONG & b) {
  return a + static_cast<LONG>((b-a+1)* Random());
}


int main(int argc, char *argv[]) {
  if (argc != 2) {
    cerr << argv[0] << ": number-of-trials\n";
    return EXIT_FAILURE;
  }

  unsigned long nuTrials = strtoul(argv[1], static_cast<char **>(0), 0);
  if (nuTrials == ULONG_MAX) {
    cerr << argv[0] << ": number-of-trials out of range\n";
    return EXIT_FAILURE;
  }

  // Prepare the random number generator.
  // erroneous expression: PutSeed(time(static_cast<time_t *>(0)) ^ (getpid() << 15 + getpid()));
  PutSeed(time(static_cast<time_t *>(0)) ^ ((getpid() << 15) + getpid()));

  // Toss the coins.
  unsigned long nuHeads, trialNu;
  for (nuHeads = 0, trialNu = nuTrials; trialNu > 0; --trialNu)
    if (Equilikely(0,1) == 1)
      ++nuHeads;

  // Print the results.
  cout << "Number of trials:\t" << nuTrials << endl;
  cout << "Number of heads:\t" << nuHeads << endl;
  cout << "Fraction of heads:\t" << (nuHeads*1.0/nuTrials) << endl;

  return EXIT_SUCCESS;
}