/**
 * qs.c
 *   A modified version of the K&R Quicksort.
 */

#include <stdio.h>
#include <string.h>
#include "sort.h"
#include "swap.h"

/**
 * qs: sort v[0]...v[size-1] into increasing alphabetical order.
 */ 
void 
sort (char *v[], int size)
{
  int i, last;

  /* If the array contains fewer than two elements, do nothing. */
  if (size <= 1)
    return;
  swap(v, 0, size/2);
  last = 0; 
  for (i = 1; i < size; i++) 
    if (strcmp (v[i], v[0]) < 0)
      swap(v, ++last, i); 
   swap(v, 0, last);
   sort (v, last); 
   sort (v+last+1, size-last-1);
} // kr_qsort