Quick sort implementation for integers in java.

QuiclkSort.java

import java.util.*;
public class QuickSort
{
  int a[];
	QuickSort(int a[])
	{
		this.a=a;
	}
	
	int[] sort()
	{
		quickSort(0,a.length-1);
		return a;
	}
	
	void quickSort(int p,int r)
	{
		if(p<r)
		{
			int q=partition(p,r);
			quickSort(p,q-1);
			quickSort(q+1,r);
		}
	}
	
	int	partition(int p,int r)
	{
		int x=a[r];
		int i=p-1;
		for(int j=p;j<r;j++)
		{
			if(a[j]<=x)
			{
				i=i+1;
			}
		}
		int temp=a[r];
		a[r]=a[i+1];
		a[i+1]=temp;
		return i+1;	
	}
}
class Test
{
	public static void main(String args[])
	{
		int a[]={5,4,3,2,1};
		QuickSort qs=new QuickSort(a);
		System.out.println(Arrays.toString(qs.sort()));
	}
}