Quicksort implementation - School HW - 21/04/2019

quicksort.c

#include <stdio.h>
#include <stdlib.h>

#define swap(x, y) ((&(x) == &(y)) ? (x) : ((x)^=(y), (y)^=(x), (x)^=(y)))
#define dim(arr) (sizeof(arr) / sizeof(*arr))

int make_partition(int arr[], int beg, int end)
{
    int pivot = arr[end], i = beg - 1;
    for (int j = beg; j < end; ++j)
    {
        if (arr[j] <= pivot)
        {
            ++i;
            swap(arr[i], arr[j]);
        }
    }
    swap(arr[i + 1], arr[end]);
    return i + 1;
}

void quicksort(int arr[], int beg, int end)
{
    if (beg > end)
        return;
    int p = make_partition(arr, beg, end);
    quicksort(arr, beg, p - 1);
    quicksort(arr, beg + 1, end);
}

int main(int argc, const char const *argv[])
{
    int arr[] = { 3, 2, 5, 4, 1 };
    int len = dim(arr);

    quicksort(arr, 0, len - 1);
    for (int i = 0; i < len; ++i)
        printf("%d ", arr[i]);
    printf("\n");

    return 0;
}