Gacha - Love Live!

gacha_ll.cpp

#include <random>
#include <iostream>
#include <unordered_map>

std::discrete_distribution<> dist({
    90,   // 90%
    9,  //  9%
    1,  //  1%
});

std::vector<std::string> itemname = { "R", "SR", "UR" };

int main()
{
    std::random_device rd;
    std::mt19937 gen(rd());

    std::unordered_map<int, int> countmap;

    for (int i = 0; i < 10000; ++i)
    {
        ++countmap[dist(gen)];
    }

    for (const auto & pair : countmap)
    {
        std::cout << itemname[pair.first].c_str() << ": " << pair.second << std::endl;
    }
}