Thread: Losing number in quick sort

I'm tinkering with a serial quick sort algorithm. Normally I use qsort() but I wanted to test this.

Somehow I loose the highest number. I can't see where I drop it. If someone here could point it out...

Code:

// Help function to quicksort, leave them in front of qsort.
void swap(float_t *left, float_t *right){
   float_t temp;
   temp = *left;
   *left = *right;
   *right = temp;
}

// Help function to quicksort, this works like a charm on random dist numbers.
int pivot(int i, int j){
   return ((i+j)/2); 
}

// Quick sort..
void quick_sort(float_t * array, int low, int high){
   int start, end, piv;
   float_t k;


  if (low < high){
     piv = pivot(low,high);
     swap(&array[low],&array[piv]);
     k = array[low];
     start = (low+1);
     end = high;

     while (start <= end)
     {
        while ((start <= high) && (array[start] <= k)){ start++; }
        while ((end >= low) && (array[end] > k)){ end--; }
        if (start < end){ swap(&array[start],&array[end]);}
     }
     swap(&array[low],&array[end]);
     quick_sort(array,low,(end-1));
     quick_sort(array,(end+1),high);
  }
}

I think I know what I did. I allocated a N size array. When I call the function I did it like this q_sort(array, 0 , N); I guess it should be N-1.

Thanks Malcolm for the input, it made me think twice about mixing up indexes.