封装c ++随机数生成器

Question

I'm building something that requires me to

template<D>
class DistributionAdapter {
public:
    /**
     * @return number generated by the distribution function.
     */
    virtual D operator()(RANDOM_NUMBER_GENERATOR& rng) = 0;
};

RANDOM_NUMBER_GENERATOR is supposed to represent the class of random number generator in c++, either std::random_device or a pseudo random number generator. Can someone tell me how should I approach this, I don't know if random number generator in c++ have a common base type

Answer 1

It's not entirely clear what you're asking, but here is a fairly easy to use function returning uniformly distributed random integers within a particular range.

#include <random>

// random number generator from Stroustrup: 
// http://www.stroustrup.com/C++11FAQ.html#std-random
int rand_int(int low, int high)
{
    static std::default_random_engine re {};
    using Dist = std::uniform_int_distribution<int>;
    static Dist uid {};
    return uid(re, Dist::param_type{low,high});
}

Answer 2

Section § 26.5.1.3 of the standard describes the requirements for random number generators .

In particular, a generator must support the function call operator :

g() T Returns a value in the closed interval [ G::min() , G::max() ] . amortized constant

So, although there is no base class shared by every single generator, the standard guarantees that the operator() will be present in each of them : you can call rng() in your function.