#include <stdio.h>
#include <stdlib.h>

void  hanoi( char peg1, char peg2, char peg3, int how_many );

main()
{
     char  peg1 = 'A',   /* origin */
           peg2 = 'B',   /* destination */
           peg3 = 'C';   /* spare */

     int   how_many;  /* number of disks initially on the origin */

     /* Prompt for and warn about the number of disks to be moved. */
     printf( "\n\tHow many disks initially on peg A?"
             "\n\tIf more than 7, the solution may seem to "
             "take forever!\n\t" );
     scanf( "%d", &how_many );

     /* Anything to move? */
     if ( how_many < 1 )
          printf( "\n\tThere's nothing to move!" );
     /* Otherwise solve with:                  */
     /*   -- peg1 as the origin                */
     /*   -- peg2 as the destination           */
     /*   -- peg3 as the spare                 */
     else
          hanoi( peg1, peg2, peg3, how_many );

     return EXIT_SUCCESS;
}

void  hanoi( char p1, char p2, char p3, int how_many )
/*    p1 -- origin
      p2 -- destination
      p3 -- spare
      how_many -- number of disks to move */
{
     /* If there is only 1 disk on p1, then move it to p2 */
     /* and quit as the problem is solved.                */
     if ( how_many == 1 ) {
        printf( "\n\n\tMove top disk from peg %c to peg %c.", 
               p1, p2 );
        return;
     }
     /* Otherwise:                                             */
     /*    (1) Move how_many - 1 disks from p1 to p3:          */
     /*        p1 is the origin, p3 is the destination,        */
     /*        and p2 is the spare.                            */
     /*                                                        */
     /*    (2) Move the top disk from p1 to p2.                */
     /*                                                        */
     /*    (3) Move how_many - 1 disks from p3 to p2:          */
     /*        p3 is the origin, p2 is the destination,        */
     /*        and p1 is the spare.                            */
     hanoi( p1, p3, p2, how_many - 1 );
     printf( "\n\n\tMove top disk from peg %c to peg %c.", p1, p2 );
     hanoi( p3, p2, p1, how_many - 1 );
}