/*
 **************************************************************************
 * Program name : 028_Tower_of_Hanoi (Version 1.00)                       *
 * Author       : Duck Wong                                               *
 * Language     : C / C++                                                 *
 * Compiler     : Boodshed Dec-C++ compiler Ver 3.95                      *
 * Computer     : PII350                                                  *
 * O/S          : Windows 98                                              *
 **************************************************************************
 * Version 1.00 : 2000/06/12 - first version                              *
 **************************************************************************
 * Description  : (a) Input the number of disks                           *
 *                (b) Output the steps                                    *
 *                (c) Try again ?                                         *
 **************************************************************************
*/
#include <iostream.h>
#include <stdlib.h>

void hanoi (char peg1, char peg2, char peg3, int disks);             // Note (1)

int main()
{
 // part 1 : declaration
 int   disks;
 char  peg1 = 'A',     // origin
       peg2 = 'B',     // destination
       peg3 = 'C',     // spare
       Again;          // run this program again

 do {
     // part 2 : Repeat asking the number of disks
     do {
         cout << "\nEnter the number of disks : ";
         cin  >> disks;
        } while (disks<=0);

     // part 3 : Call the function hanoi
     hanoi(peg1, peg2, peg3, disks);

     // part 4 : try again ?
     cout << "\n\n\aTry again (Y/N) : ";
     cin  >> Again;
     cout << "\n";
    } while (Again=='Y' || Again=='y');
 cout << "\n" << endl;

 system("PAUSE");
 return 0;
}

void hanoi (char p1, char p2, char p3, int disks)
{
 if (disks==1)
   {
    cout << "\n\tMove top disk from peg_" << p1 << " to peg_" << p2 <<".";
    return;
   }
 // Move (n-1) disks from peg1 to peg3
 hanoi(p1, p3, p2, disks-1);
 // Move the last disk from peg1 to peg2
 cout << "\n\tMove top disk from peg_" << p1 << " to peg_" << p2 <<".";
 // Move (n-1) disks from peg3 to peg2
 hanoi(p3, p2, p1, disks-1);
}

/* Notes
   (1) Let us assume that the aim is moving all disks from peg1 to peg2.
       Moving n disks can be viewed in terms of moving only (n-1( disks
       as follows :

       (a) Move (n-1) disks from peg1 to peg3
       (b) Move the last disk from peg1 to peg2
       (c) Move (n-1) disks from peg3 to peg2

       To solve this program, the hanoi function needs 4 parameters :
       (a) The peg on which these disks are initially threaded
       (b) The peg to which this stack of disks is to be moved
       (c) The peg to be used as a temportary holding area
*/