std::discrete_distribution

Since C++11

Header: <random>

std::discrete_distribution produces random integers on the interval [0,n), where the probability of each individual integer i is defined as wi/S, that is the weight of the ith integer divided by the sum of all n weights.

# Declarations

template< class IntType = int >
class discrete_distribution;

(since C++11)

# Example

#include <iomanip>
#include <iostream>
#include <map>
#include <random>
 
int main()
{
    std::random_device rd;
    std::mt19937 gen(rd());
    std::discrete_distribution<> d({40, 10, 10, 40});
    std::map<int, int> map;
 
    for (int n = 0; n < 1e4; ++n)
        ++map[d(gen)];
 
    for (const auto& [num, count] : map)
        std::cout << num << " generated " << std::setw(4) << count << " times\n";
}