cs-lab34/histogram.cpp

#include "histogram.h"
#include <vector>

void find_minmax(const std::vector<double>& numbers, double& min, double& max)
{
    min = numbers[0];
    for (double x : numbers)
    {
        if (x < min)
        {
            min = x;
        }
        else if (x > max)
        {
            max = x;
        }
    }
}

std::vector<std::size_t> make_histogram(const std::vector<double> &numbers, std::size_t bin_count)
{
    double min = numbers[0];
    double max = numbers[0];
    find_minmax(numbers, min, max);
    double bin_size = (max - min) / bin_count;
    std::vector<std::size_t>bins(bin_count);

    for (std::size_t i = 0; i < numbers.size(); i++)
    {
        bool found = false;
        for (std::size_t j = 0; (j < bin_count - 1) && !found; j++)
        {
            auto lo = min + j * bin_size;
            auto hi = min + (j + 1) * bin_size;
            if ((lo <= numbers[i]) && (numbers[i] < hi))
            {
                bins[j]++;
                found = true;
            }
        }
        if (!found)
        {
            bins[bin_count - 1]++;
        }
    }
    double b;
    for (std::size_t i = 0; i < bin_count-1; i++)
    {
        if (bins[i] > bins[i+1])
        {
            b = bins[i];
            bins[i] = bins[i + 1];
            bins[i + 1] = b;
        }
    }
    return bins;
}