quickSort.java

public class quickSort {

    /**
     * @param args
     */
    public static void main(String a[])
    {
        int i;
        int array[] = {12,9,4,99,120,1,3,10,13};

        System.out.println(" Quick Sort\n\n");
        System.out.println("Values Before the sort:\n");
        for(i = 0; i < array.length; i++)
            System.out.print( array[i]+"  ");
        System.out.println();
        quick_srt(array,0,array.length-1);
        System.out.print("Values after the sort:\n");
        for(i = 0; i <array.length; i++)
            System.out.print(array[i]+"  ");
        System.out.println();
        System.out.println("PAUSE");
    }

    public static void quick_srt(int array[],int low, int n)
    {
        int lo = low;
        int hi = n;
        if (lo >= n)
        {
            return;
        }
        int mid = array[(lo + hi) / 2];
        while (lo < hi)
        {
            while (lo<hi && array[lo] < mid)
            {
                lo++;
            }
            while (lo<hi && array[hi] > mid)
            {
                hi--;
            }
            if (lo < hi)
            {
                int T = array[lo];
                array[lo] = array[hi];
                array[hi] = T;
            }
        }
        if (hi < lo)
        {
            int T = hi;
            hi = lo;
            lo = T;
        }
        quick_srt(array, low, lo);
        quick_srt(array, lo == low ? lo+1 : lo, n);
    }
}