quick sort

quick.c

//quick sort
#include<stdio.h>

void quicksort(int*arr,int left, int right);
int partition(int *arr,int left,int right);

int main()
{
	int arr[6]={5,4,1,2,8,3};
	int i;
	int n = sizeof(arr)/sizeof(int);
	
	quicksort(arr,0,n-1);

	for(i=0;i<n;i++)
        printf("%d ",arr[i]);
	return 0;
}

void quicksort(int*arr,int left, int right)
{
	int p;
	if(left>=right)
	return;
	else
	p = partition(arr,left,right);  // partition the array.  arr[p] at its correct position
	quicksort(arr,left,p-1);
	quicksort(arr,p+1,right);
}

int partition(int *arr,int left,int right)
{
	int i=left,j=right-1;
	int t;
	int pivot = arr[right];
	while(i<=j)
	{
		while(arr[i]<pivot)i++;
		while(arr[j]>pivot)j--;
		if(i<=j)
		{
			t = arr[i];
			arr[i] = arr[j];
			arr[j] = t;
		}
		else
		{
			t = arr[i];
			arr[i] = pivot;
			arr[right] = t;
		}
	}
	return i;
}