private void quickSort(int low, int high) {
		int i=low,j=high;
		int pivot=numbers[low+(high-low)/2];
		while (i<j){
			while(numbers[i]<pivot){
				i++;
			}
			while(numbers[j]>pivot){
				j--;
			}
			if(i<=j){
				exchange(i,j);
				i++;
				j--;
			}
		}
		if(low<j){
			quickSort(low, j);
		}
		if(i<high){
			quickSort(i, high);
		}
	}