Get the largest, average and smallest value

Question

To simplify my question, I will use the pixel as a template.

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What is the fastest way I can calculate which value of a pixel is highest, median and lowest? For example:

unsigned char pixel[] = {128, 255, 64};
unsigned char highest, median, lowest;

get_pixel_values_priority(pixel, &highest, &median, &lowest);
printf("Highest %u\nMedian %u\nLowest %u", highest, median, lowest);

Should result:

Highest 255
Median 128
Lowest 64

Answer 1

Since you tagged this with C++, I would use std::vector objects mixed with the std::sort() algorithm for making it easy to find these stats. Here's a simple example.

#include <algorithm>
#include <iostream>
#include <vector>

int main() {
    std::vector<float> numbers = { 1, 4, 3, 2 };

    std::sort(numbers.begin(), numbers.end());

    // numbers = { 1, 2, 3, 4 }

    float min = numbers.front();
    float max = numbers.back();

    float median;
    if (numbers.size() % 2) {   // odd number of elements
        median = numbers[numbers.size() / 2];
    }
    else {                      // even number of elements
        median = (numbers[numbers.size() / 2] + numbers[numbers.size() / 2 - 1]) / 2;
    }
}