C++: random number generator

random_probability_generator.cpp

#include <iostream>
#include <iomanip>
#include <random>

// this template comes from http://stackoverflow.com/a/39183450/2227743
template<class Ty = double, class = std::enable_if<std::is_floating_point<Ty>::value>>
class random_probability_generator {
public:
    // default constructor uses single random_device for seeding
    random_probability_generator()
    : mt_eng{std::random_device{}()}, prob_dist(0.0, 1.0) {}
    Ty next() { return prob_dist(mt_eng); }
    Ty generate() { return next(); }
private:
    std::mt19937 mt_eng;
    std::uniform_real_distribution<Ty> prob_dist;
};

// usage
int main(int argc, const char * argv[]) {
    // default: for double.
    // add a type in the template to change it,
    // ex: random_probability_generator<float> pgen;
    random_probability_generator<> pgen;
    // let's make some random bits
    for (int i = 0; i < 1000; i++) {
        double p = pgen.generate();
        // fmod(floor(p*10), 2) gives a random number between 0 and 1 (because modulo 2)
        // use modulo 3 for rnd between 0 and 2, mod 4 for rnd between 0 and 3, etc
        double r = fmod(floor(p*10), 2);
        std::cout << r;
    }
    std::cout << std::endl;
    return 0;
}