roulette wheel selection using std::discrete_distribution

roulette.cpp

#include <array>
#include <iostream>
#include <random>

int main() {
    constexpr std::array<double, 3> fitness_values = {1, 1.5, 2};
    // Constructor is O(n)
    std::discrete_distribution<std::size_t> dist(fitness_values.begin(), fitness_values.end());
    std::array<size_t, 3> table;
    table.fill(0);
    std::mt19937 random_engine;
    for (auto i = 0; i < 100000; ++i) {
        // Sampling is O(1)
        ++table[dist(random_engine)];
    }
    for (auto i = 0; i < 3; ++i) {
        std::cout << i << " was selected " << table[i] << " times." << std::endl;
    }
}