Compute PI

compute_pi.cpp

#include <cstdlib>
#include <iostream>

using namespace std;

int main(int, char**) {
    long long inside = 0;

    for(long long ii = 0; ii < 1e9; ++ii) {
        double x = rand()/double(RAND_MAX);
        double y = rand()/double(RAND_MAX);

        if(x*x+y*y <= 1.0) {
            ++inside;
        }

        if(ii % 1000000 == 0) {
            double ratio = double(ii+1)/inside;
            cout << "i: " << ii << "ratio: " << ratio;
            cout << ", pi: " << 4.0/ratio << endl;
        }

    }

    return 0;
}