#include <iostream>
using namespace std ;

void quicksort ( int [], int, int ) ;
int split ( int [], int, int ) ;

int main()
{
    int arr[] = {11, 2, 9, 13, 57, 25, 17, 1, 90, 3};
    int i ;

    cout << "Quick sort" << endl ;
    cout << "Array before sorting:" << endl ;
    for (i=0; i<10; i++)
        cout << arr[i]<< "\t" ;

    quicksort ( arr, 0, 9 ) ;

    cout << endl << "Array after sorting:" << endl ;
    for ( i = 0; i < 10 ; i++ )
        cout << arr[i] << "\t";

    return 0 ;

}

void quicksort (int a[], int lower, int upper )
{    
    int i;

    if ( upper > lower)
    {
        i = split (a, lower, upper ) ;
        quicksort (a, lower, i-1 ) ;
        quicksort (a, i+1, upper) ;
    }
}

int split ( int a[], int lower, int upper )
{
    int p, q, num, temp ;

    p = lower + 1;
    q = upper ;
    num = a[lower] ;

    while ( q >= p )
    {
        while (a[p] < num )
            p++;
        while (a[q] < num )
            q-- ;

        if ( q > p )
        {
            temp = a[p] ;
            a[p] = a[q] ;
            a[q] = temp ;
        }
    }

    temp = a[lower] ;
    a[lower] = a[q] ;
    a[q] = temp;

    return q ;
}

Quick sort
Array before sorting:

Killed