#include <iostream>
#include <random>
 
struct RandNormGen {
    std::random_device rd;
    std::mt19937 gen;
    std::normal_distribution<float> normalDist;
 
    RandNormGen() {
        gen = std::mt19937(rd());
        normalDist = std::normal_distribution<float>(0, 1);
    }
 
    float randFloat(float sigma, float mean = 0) {
        float r = normalDist(gen) * sigma + mean;
        return r;
    }
};
 
int main() 
{
	RandNormGen r;
	std::cout << r.randFloat(1.0f) << "\n";
	return 0;
}

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