//  Quicksort algorithm for n elements 
//  in a Monitored array, a.


#include <iostream.h>
#include "array.h"

extern MArray a;
void swap (int,int);
void quicksrt (int,int);

void quick (int n)
{
   quicksrt (0,n-1);
}

void quicksrt (int first, int last)
{  int c,t;
   int right, left;
   c = a[first];
   right = first + 1;
   left = last;
   // while (right<last && a[right]<c) right++;
   while (a[left]>c) left--;
   while (right<last && a[right]<c) right++;
   while (right<left) 
     {  swap (right,left);
	// while (a[right]<c) right++;
	while (a[left]>c) left --;
	while (a[right]<c) right++;
     }
   t = a[left];			// a[first] = a[left]
   a[left] = c;
   a[first] = t;
   // if (first<left-1) quicksrt (first, left-1);
   if (last>left+1) quicksrt (left+1, last);
   if (first<left-1) quicksrt (first, left-1);
}