C Program For Quick Sorting

  // Quick Sort //
  
 #include <iostream.h>
 #include <stdio.h>
 #include <dos.h>
 #include <conio.h>

 #define   MAX 15

 #define ValueOf( x )  ( x.value() )
 #define Exchange( x , y )  ( x.exchange(y) )

 class element
 {
  int _value;
  int _color;
 public:
  element() { _color = 15; }
  void get()
  {
   scanf ( "%d", &_value );
  }
  int value (){ return _value;}
  void exchange ( element &e )
  {
   element temp;
   temp = e;
   e = *this;
   *this = temp;
  }

  void setcolor ( int col ) { _color = col; }

  void show()
  {
   textbackground ( _color );
   if ( _color == 15 )
   {
    textcolor ( 0 );
   }
   else
   {
    textcolor ( 15 );
   }
   cprintf ( " %d " , _value );
   printf ( " " );
  }
 };
 /*
 int element :: value ()
 {
  return _value;
 }
   */
 void QuickSort ( element * , int , int );
 int partition ( element * , int  , int  );

 void Display  ( element *A , int p , int r );
 void main()
 {
  element array[MAX];
  int i = 1;

  textbackground ( 0 );
  textcolor ( 15 );
  clrscr ();
  printf ( "
 Enter %d elements:- 
 > ", MAX - 1 );
  for ( i = 1; i < MAX; i++ )
   array[i].get();

  printf ( "
" );
  for ( i = 1; i < MAX; i++ )
   array[i].show();

  getch();
  printf ( "
" );
  QuickSort ( array , 1 , MAX - 1 );

  printf ( "
 " );
  for ( i = 1; i < MAX; i++ )
   array[i].show();

  getch();
 }

 void QuickSort ( element *A , int p , int r )
 {
  int q;
  if ( p < r )
  {
   q = partition ( A , p , r );
   QuickSort ( A , 1 , q - 1 );
   QuickSort ( A , q + 1 , r );
  }
 }

 int partition ( element *A , int p , int r )
 {
  int key , i = 1 , j = 1;

  key = ValueOf ( A[r] );
  A[r].setcolor ( RED );

  i = p - 1;
  for ( j = p ; j <= r; j++ )
  {
   if ( ValueOf ( A[j] ) <= key )
   {
    i = i + 1;
    Exchange ( A[j] , A[i] );
   }
   else
   {
//    A[j].setcolor ( BLUE );
   }
   Display ( A  , 1 , MAX );
   delay ( 100 );
  }

  A[i].setcolor ( GREEN );
  Display ( A  , 1 , MAX );
  printf ( "
 > %d at correct position. ", ValueOf ( A[i] ) );
  return i ;
 }

 void Display  ( element *A , int p , int r )
 {
  if ( wherey () > 23 )
  {
   getch();
   textbackground ( 0 );
   textcolor ( 15 );
   clrscr();
  }
  printf ( "

 " );
  for ( int i = p; i < r; i++ )
  {
   A[i].show();
  }
 }