quick_sort.c

// Solution for integer array sorting in place using the quicksort algorithm
#include <stdio.h>
#include <stdlib.h>

void swap(int *a, int *b)
{
	int t = *a;
	*a = *b;
	*b = t;
}

int partition(int arr[], int low, int high)
{
	int pivot = arr[high];
	int i = (low -1);
	for (int j = low; j <= high-1; j++)
	{
		if(arr[j] < pivot)
		{
			i++;
			swap(&arr[i], &arr[j]);
		}
	}
	swap(&arr[i+1], &arr[high]);
	return (i+1);
}

void quickSort(int arr[], int low, int high)
{
	if(low < high)
	{
		int pi = partition(arr, low, high);
		quickSort(arr, low, pi - 1);
		quickSort(arr, pi + 1, high);
	}
}

void printArray(int arr[], int n)
{
	int i = 0;
	for(; i<n; i++)
		printf("%d ", arr[i]);
	printf("\n");

}

int main() {
	int arr[] = {10, 7, 8, 9, 1, 5};
	int n = sizeof(arr)/sizeof(arr[0]);
	printArray(arr,n);
	quickSort(arr,0,n-1);
	printArray(arr,n);
	return 0;
}