#include <iostream>
#include <algorithm>
#include <random>

int main() {

	std::mt19937 rnd{std::random_device{}()}; // Probably created in main

	const std::vector<double> ys = {-0.2, -0.3, -0.4, 0.4, 0.5};
	std::uniform_int_distribution<> dis(0, ys.size() - 1);
	
	for (int i = 0; i != 10; ++i) {
        double y = ys[dis(rnd)];
	    std::cout << y << std::endl;
	}
}