#include "stdafx.h"
#include <windows.h>
#include <stdio.h>
#include <iostream>
#include <ctime>

using namespace std;

#define beg 10.0
#define end 20.0
#define NTh 4//количество потоков
#define NRec 1000.0//количество прямоугольников

double Sum = 0;
double x=beg+((end - beg) / (2*NRec));

void WINAPI ThreadProc()
{
    for (double i = 0; i < NRec / NTh; i++)
    {
        Sum += (x * x -x -5 )*((end - beg) / NRec);
        x += (end - beg) / NRec;
    }

}

int main(int argc, char* argv[])
{
    setlocale(LC_CTYPE, "rus");
    HANDLE Thread[NTh];
    double start_time = clock();
    for (int i = 0; i < NTh; i++)
        Thread[i] = CreateThread(0, 0, (LPTHREAD_START_ROUTINE)ThreadProc, 0, 0, 0);
    WaitForMultipleObjects(NTh, Thread, TRUE, INFINITE);
    double finish_time = clock();
    cout << "number rectangles: " << NRec << endl;
    cout << "number threads: " << NTh<< endl;
    cout << "time: " << (finish_time - start_time) / 1000 << endl;
    cout << "result : " << Sum << endl;
    cout << "error: " << Sum/(6400/3.) << endl;
    system("pause");
    return 0;
}