C++11 random numbers

Question

I need to generate random numbers, but from as wide a range as possible (64 bit at least). I don\'t care if the distribution is perfect, so std::rand() would wo

Answer 1

We could easily wrap a random number generator engine into srand/rand-like methods like this:

#include 
#include 

struct MT19937 {
private:
    static std::mt19937_64 rng;
public:
    // This is equivalent to srand().
    static void seed(uint64_t new_seed = std::mt19937_64::default_seed) {
        rng.seed(new_seed);
    }

    // This is equivalent to rand().
    static uint64_t get() {
        return rng();
    }
};

std::mt19937_64 MT19937::rng;


int main() {
    MT19937::seed(/*put your seed here*/);

    for (int i = 0; i < 10; ++ i)
        std::cout << MT19937::get() << std::endl;
}

(Like srand and rand, this implementation does not care about thread-safety.)

Well the wrapper functions are so trivial that you could just use the engine directly.

#include 
#include 

static std::mt19937_64 rng;

int main() {
    rng.seed(/*put your seed here*/);

    for (int i = 0; i < 10; ++ i)
        std::cout << rng() << std::endl;
}