ExponentialDistribution.cpp

// exponential_distribution
#include <iostream>
#include <random>

int main()
{
    const int nrolls = 10000;  // number of experiments
    const int nstars = 100;    // maximum number of stars to distribute
    const int nintervals = 10; // number of intervals

    std::default_random_engine generator;
    std::exponential_distribution<double> distribution(3.5);

    int p[nintervals] = {};

    for (int i = 0; i < nrolls; ++i) {
        double number = distribution(generator);
        if (number < 1.0) ++p[int(nintervals * number)];
    }

    std::cout << "exponential_distribution:" << std::endl;
    std::cout << std::fixed; std::cout.precision(1);

    for (int i = 0; i < nintervals; ++i) {
        std::cout << float(i) / nintervals << "-" << float(i + 1) / nintervals << ": ";
        std::cout << std::string(p[i] * nstars / nrolls, '*') << std::endl;
    }

    return 0;
}