/**
 *
 *  @file    CNpThreadsBoostV1.cpp
 *
 *  @author  D. Mathieu, M. Laporte
 *
 *  @date    23/09/2008
 *
 *  @version 2.0
 *
 *  @brief   Calcul parallele de CNp
 *
 **/
#include <iostream>
#include <vector>
#include <sstream>

#include <boost/thread/thread.hpp>
#include <boost/tr1/functional.hpp>  // ou <functional>

//#include "CstCodErr.h"

using namespace std;
using namespace boost;

//using namespace nsUtil;             // KExcArg

namespace
{
    enum { KExcArg  = 253 };    // Erreur d'arguments de main()
    void CNp (unsigned N, unsigned p, unsigned * pRes)
    {
        if  (N == p)
        {
            *pRes = 1;
            return;
        }
        if (p == 1)
        {
            *pRes = N;
            return;
        }

        unsigned r1;
        unsigned r2;

        thread_group groupThreads;
        groupThreads.create_thread (bind (CNp, N - 1, p - 1, & r1));
        groupThreads.create_thread (bind (CNp, N - 1, p    , & r2));

        groupThreads.join_all ();
        *pRes = r1 + r2;

    } // CNp()

} // namespace

int main (int argc, char * argv [])
{
    if (argc != 3)
    {
         cerr << "Usage : " << argv [0] << " <N> <p>\n";
         return KExcArg;
    }
    unsigned N;
    {
        istringstream is (argv [1]);
        is >> N;
    }
    unsigned p;
    {
        istringstream is (argv [2]);
        is >> p;
    }
    cout << "C (" << N << ", " << p << ") = " << flush;

    unsigned result;
    thread thr (bind (CNp, N, p, & result));

    thr.join ();

    cout << result << '\n';

    return 0;

} // main()