Normal distribution from uniform distribution

gistfile1.cpp

#include <iostream>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <vector>
#include <algorithm>
#include <array>

float getVal() {

    float t2 = 0;
    int n = 1000;

    for (int i = 0; i < n; ++i) {
        t2 += float(rand()) / float(RAND_MAX);
    }

    t2 /= n;

    return (t2 - 0.5)*sqrt(12*n);
}

int main()
{    
    srand(time(0));

    //generate seq
    std::vector<float> seq;
    for (int i = 0; i < 300; ++i)
        seq.push_back(getVal());


    //analize
    auto minmax = std::minmax_element(seq.begin(), seq.end());
    auto constexpr zonesCount = 10;
    std::array<int, zonesCount> stat = {0};

    auto zoneSize = (*minmax.second - *minmax.first)/(zonesCount-1);

    for (auto el: seq)
        stat[(el - *(minmax.first))/zoneSize]++;

    //output
    for (auto el: stat) {
        for (int i = 0; i < el; ++i)
            std::cout << "o";
        std::cout << std::endl;
    }
}