Math Truth!

BirthdayBuster.cpp

#include <iostream>
#include <random>
#include <sstream>
using namespace std;

void RollDice(mt19937_64& mt, int n)
{
    uniform_int_distribution<int> distribution(1, 30);

    int matchCount = 0;

    for (int i = 0; i < n; ++i)
    {
        int a = distribution(mt);
        int b = distribution(mt);

        matchCount += a == b;
    }

    cout << matchCount << " matches out of " << n << " random pairs" << endl;
}

int main(int argc, char** argv)
{
    mt19937_64 mt;

    for (int i = 1; i < argc; ++i)
    {
        stringstream ss;
        ss << argv[i];

        int n;
        if (ss >> n) RollDice(mt, n);
    }

    return 0;
}