I was trying to check how random numbers are actually random, but then I encountered a problem in which the line of code v.procs_counter++; for some reason changes the object’s variable only once

#include <iostream>
#include <random>
#include <windows.h>

class Random {
    public:
        std::string id;
        int min_value, max_value;
        int procs_counter = 0;
    
    Random (int minv, int maxv, std::string s) {
        this->min_value = minv;
        this->max_value = maxv;
        this->id = s;
    }
};

int main() {
    int global_min_value = 0;
    int global_max_value = 100;

    std::random_device dev;
    std::mt19937_64 rng(dev());
    std::uniform_int_distribution<std::mt19937_64::result_type> RNGrange(global_min_value, global_max_value);

    Random r1(1, 30, "30%");
    Random r2(31, 100, "70%");
    auto arr = {r1, r2};

    int total_attempts = 0;
    
    while (true) {
        total_attempts++;
        int RNGcheck = RNGrange(rng);

        for (auto v: arr) {
            if (RNGcheck >= v.min_value & RNGcheck <= v.max_value) {
                v.procs_counter++;

                std::cout << v.id << "'s average attempts: " << v.procs_counter * 100/total_attempts << std::endl;
            }
        }

        Sleep(60);
    }

    return 0;
}

I’ve tried doing += 1 instead of ++ and also tried doing v.procs_counter = v.procs_counter + 1 and nothing helped me. It’s always 1 * 100/total_attempts instead of number 1 actually changing