A few wrap of sorting algorithms to remember a little of pointer arithmetics in C

sort.c

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

#include <limits.h>

#define MAXL 15
#define MAX_VALUE 10;

int* generate(void) {
	int i;
	int* array = (int*) malloc(MAXL * sizeof(int));

	if (array == NULL) {
		fprintf(stderr, "unable to allocate memory");
		exit(0);
	}

	for (i = 0; i < MAXL; i++) {
		array[i] = rand() % MAX_VALUE;
	}
	
	return array;
}

void print(int* array, int len) {
	int i;

	for (i = 0; i < len; i++) {
		printf("%d ", *(array + i));
	}
	
	printf("\n");
}

//O(n^2)
void bubble_sort(int* array, int len) {
	int i, j;

	for (i = 0; i < len; i++) {
		for (j = i + 1; j < len; j++) {
			if (array[j] < array[i]) {
				int tmp = array[i];
				array[i] = array[j];
				array[j] = tmp;
			}
		}
	}
}

//O(n^2)
void selection_sort(int* array, int len) {	
	int i, j;
	
	for (i = 0; i < len; i++) {
		int pos = i;
		int value = array[i];

		for (j = i; j < len; j++) {
			if (array[j] < value) {
				value = array[j];
				pos = j;
			}
		}

		if (pos != i) {
			int tmp = array[i];
			array[i] = array[pos];
			array[pos] = tmp;
		}
	}
}

//O(n^2)
void insertion_sort(int* array, int len) {
	int i, j;
	
	for (i = 1; i < len; i++) {
		j = i;

		while (j - 1 >= 0 && array[j] < array[j - 1]) {
			int tmp = array[j];
			array[j] = array[ + j - 1];
			array[j - 1] = tmp;
			j -= 1;
		}
	}
}

//Helper method for quicksort
void quick_sort_helper(int* array, int l, int r, int len) {
	int bound_l = l;
	int bound_r = r;

	int pivot = array[(l + r) / 2];

	do {
		while (array[l] < pivot) {
			l += 1;
		}
		
		while (array[r] > pivot) {
			r -= 1;
		}

		if (l <= r) {
			int tmp = array[l];
			array[l] = array[r];
			array[r] = tmp;

			l += 1;
			r -= 1;
		}
	} while (l <= r);

	if (r > bound_l) {
		quick_sort_helper(array, bound_l, r, len);
	}
	if (l < bound_r) {
		quick_sort_helper(array, l, bound_r, len);
	}
}

//O(n*log(n)) but can be O(n^2)
void quick_sort(int* array, int len) {
	quick_sort_helper(array, 0, len - 1, len);
}

int main(int argc, char** argv) {
	srand(time(NULL));

	int* array = generate();

	print(array, MAXL);
	quick_sort(array, MAXL);
	print(array, MAXL);
	
	free(array);

	return 0;
}