Thread: QuickSort method

 
void quicksort (int[] a, int lo, int hi)
{
//  lo is the lower index, hi is the upper index
//  of the region of array a that is to be sorted
    int i=lo, j=hi, h;
 
    // comparison element x
    int x=a[(lo+hi)/2];
 
    //  partition
    do
    {    
        while (a[i]<x) i++; 
        while (a[j]>x) j--;
        if (i<=j)
        {
            h=a[i]; a[i]=a[j]; a[j]=h;
            i++; j--;
        }
    } while (i<=j);
 
    //  recursion
    if (lo<j) quicksort(a, lo, j);
    if (i<hi) quicksort(a, i, hi);
}

Do you guys see anything wrong with this quickSort method? This will not sort.

Example: If I type:
2
4
1
3

I expect the results to be:
1
2
3
4

when I hit the "sort" button. But I don't.

Your help is appreciated!

What results do you get for the input you show?

Try debugging your code by adding printlns to show the logic flow and how variable values change.
Be sure to add id Strings to the prints to be able to identify them.