Sorting and searching in C. Slightly meh recursion in maxHeap…

sort_find.c

#include <stdio.h>

#define LEFT(x) (2*(x)+1)
#define RIGHT(x) (2*(x)+2)
#define PARENT(x) (((x)-1)/2)

void swap (int* a, int i, int j) {
    int t = a[i];
    a[i] = a[j];
    a[j] = t;
}

void maxHeap (int* a, int i, size_t size)
{
    int l = LEFT(i);
    int r = RIGHT(i);
    int m = -1;
    m = (l < size && a[l] > a[i]) ? l : i;
    m = (r < size && a[r] > a[m]) ? r : m;
    
    if (m != i) {
        swap(a, i, m);
        maxHeap(a, m, size);
    }
}

void buildMaxHeap (int* array, size_t size)
{
    int hs = size / 2;
    for (int i = hs; i > 0; i--) {
        maxHeap(array, hs - i, size);
    }
}

void heapSort (int* array, size_t size) {
    buildMaxHeap(array, size);
    for (int i = size - 1; i >= 0; i--) {
        swap(array, 0, i);
        maxHeap(array, 0, i);
    }
}

int find (int elem, int* array, size_t size) {
    int pos = -1;
    int low = 0;
    int high = size - 1;
    
    while (low < high) {
        int mid = low + ((high - low) / 2);
        if (array[mid] < elem) {
            low = mid;
        } else if (array[mid] > elem) {
            high = mid;
        } else {
            pos = mid;
            break;
        }
    }
    
    return pos;
}

int main(int argc, const char * argv[]) {
    // insert code here...
    int numbers [] = {1,9,2,8,3,7,4,6,5};
    heapSort(numbers, 9);
    int pos = find (7, numbers, 9);
    return 0;
}