cs-lab34/histogram.cpp

#include "histogram.h"
#include "svg.h"
using namespace std;

//  Ïîèñê ìàêñèìóìà è ìèíèìóìà ñðåäè îöåíîê.

void find_minmax(const vector<double>& numbers, double& min, double& max)
{
    min = numbers[0];
    max = numbers[0];

    for (double x : numbers)
        {
            if (x < min)
                min = x;
            else if (x > max)
                max = x;
        }
}

vector<size_t> make_histogram(const vector<double>& numbers, size_t bin_count)
{
//  Ïîèñê ìàêñèìóìà è ìèíèìóìà ñðåäè îöåíîê.
    double min, max;

    find_minmax(numbers, min, max);
//  Ñîçäàíèå êîðçèí äëÿ äàëüíåéøåé ñîðòèðîâêè îöåíîê ïî íèì.

    double bin_size = (max - min) / bin_count;

    vector<size_t> bins(bin_count);

    for (size_t i = 0; i < bin_count; i++)
        bins[i] = 0;

//  Ñîðòèðîâêà îöåíîê ïî êîðçèíàì.

    for (size_t i = 0; i < numbers.size(); i++)
        {
            bool found = false;
            for (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]++;
        }
    return bins;
}

//  Ñîçäàíèå ãèñòîãðàììû íà îñíîâàíèè êîðçèí â ôîðìàòå SVG.

void show_histogram_svg(const vector<size_t>& bins)
{
//  Íåîáõîäèìûå êîíñòàíòû.
    const auto IMAGE_WIDTH = 400;
    const auto IMAGE_HEIGHT = 300;
    const auto TEXT_LEFT = 20;
    const auto TEXT_BASELINE = 20;
    const auto TEXT_WIDTH = 50;
    const auto BIN_HEIGHT = 30;
    size_t max_bins = bins[0];

//  Ïîèñê ìàêñèìàëüíîé êîðçèíû.

    for (size_t x: bins)
        if (x > max_bins)
            max_bins = x;

//  Âûðàâíèâàíèå ãèñòîãðàììû ïî ìàêñèìàëüíîìó ñòîëáöó.

    const auto BLOCK_WIDTH = (IMAGE_WIDTH - TEXT_WIDTH)/max_bins;//BLOCK_WIDTH = 10

    svg_begin(IMAGE_WIDTH, IMAGE_HEIGHT);
    double top = 0;
    for (size_t bin : bins)
        {
            const double bin_width = BLOCK_WIDTH * bin;
            svg_text(TEXT_LEFT, top + TEXT_BASELINE, to_string(bin));
            svg_rect(TEXT_WIDTH, top, bin_width, BIN_HEIGHT);
            top += BIN_HEIGHT;
        }
    svg_end();
}