/* QSORT Algorithm (p87 of K&R)
Defines sort on a sub array of 
	left <= location <= right
of an array of integers
*/
#include <stdio.h>
void 	QSort(int v[], int left, int right){ 
	int pivot,last,i;
	if(left>=right) 
	/* If left=right there is a single array element
	it is already sorted 
	*/
		return;
	/* Select "middle" element as pivot 
	*/
	pivot= (left+right)/2; 
	/* Puts the pivot value in the left hand location 
	makes it easy to sweep through the rest of the elements 
	*/
	Swap(v,left,pivot);
	/* last is the last location in the subarray that has
	been tested <= the pivot value 
	*/
	last=left;
	for(i=left+1; i<=right; i++){
		/* sweeps through the array 
		if v[i]< pivot is moved left and
		stays put otherwise. last is 
		incremented to keep track of the split point 
		*/ 
		if(v[i]<v[left]){
			Swap(v,++last,i);
			};
		};
	/* Restores pivot element 
	to a correct location
	*/
	Swap(v,left,last);
	/* Diagnostic print for Illustration */
	printf("{%i,%i,%i}\n", left, last, right);
	/* Dispatches QSort on unsorted "halves" */
	QSort(v,left,last-1);
	QSort(v,last+1,right);
	
}