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

using namespace std;

unsigned long long N = 1000000000;

double pi()
{
    double x, y;
    unsigned long long n = 0;
    double postep = 0.1;

    srand(time(nullptr));
    cout << "Wykonano 0%\n";
    for(unsigned long long i = 0; i < N; ++i)
    {
        if(1.0 * i / N >= postep)
        {
            system("cls");      // odświeżenie ekranu konsoli
            cout << "Wykonano " << 100.0 * i / N << "%\n";
            postep += 0.1;
        }
        x = 1.0 * rand() / RAND_MAX;
        y = 1.0 * rand() / RAND_MAX;
        if(x*x + y*y <= 1)
            ++n;
    }
    system("cls");
    return 4.0 * n / N;
}

int main()
{
    double wynik = pi();
    cout << "Liczbe PI oszacowano na " << wynik << endl;
    return 0;
}