#include <iostream>
#include <vector>
#include <cmath>
#include <thread>
#include <windows.h>
#include <cstdlib>
#include <ctime>
using namespace std;
int flags=0;

void filler(int start_pos, int end_pos, vector<double> &data)
{
for (;start_pos<end_pos; start_pos++)
    {
    data[start_pos]=start_pos;
    for (int i=0; i<400; i++){ //insert some timeconsuming random operations in here
    data[start_pos]=sin(data[start_pos]);
    data[start_pos]=cos(data[start_pos]);}
    }
    flags++;
}


int main()
{
    clock_t begin, end;
    double timer;
    vector<double> data(100000);
    //fill_1(0, 100000, data);
    cout << "Performing 1 thread performance test\n";
    begin=clock();
    thread t(filler,0, 100000, std::ref(data));
    t.detach();
    while(1)
    {
        Sleep(20);
        if (flags==1)
            break;
    }
    end=clock();
    timer=(double)(end-begin)*1000.0 / CLOCKS_PER_SEC;
    data.clear();
    cout << "Test #1 took " << timer << " miliseconds\n";
    flags=0;
    cout << "Performing 2 threads performance test\n";
    begin=clock();
    thread g(filler, 0, 50000, std::ref(data));
    g.detach();
    thread h(filler, 50001, 100000, std::ref(data));
    h.detach();
        while(1)
    {
        Sleep(20);
        if (flags==2)
            break;
    }
    data.clear();
    end=clock();
    timer=(double)(end-begin)*1000.0 / CLOCKS_PER_SEC;
    cout << "Test #2 took " << timer << " miliseconds\n";
    cout << "Performing 4 threads performance test\n";
    begin=clock();
    flags=0;
    thread a(filler,0, 25000, std::ref(data));
    a.detach();
    thread b(filler, 25001, 50000, std::ref(data));
    b.detach();
    thread c(filler, 50001, 75000, std::ref(data));
    c.detach();
    thread d(filler,75001, 100000, std::ref(data));
    d.detach();
           while(1)
    {
        Sleep(20);
        if (flags==4)
            break;
    }
     end=clock();
    timer=(double)(end-begin)*1000.0 / CLOCKS_PER_SEC;
    cout << "Test #3 took " << timer << " miliseconds\n";
    system("PAUSE");
    return 0;
}