\ Tower of hanoi                Written by : Luke Lee
\ A demonstration for recursive program for MetaForth
\ Ported to 4tH by J.L. Bezemer - September 1999

[NEEDS lib/enter.4th]
[NEEDS lib/pickroll.4th]

: MOVE-DISK ( source destination temp n -- )
    DUP 0<> IF
       DUP 1- >R 3 PICK 2 PICK 4 PICK R> RECURSE
       ." Move disc " DUP . ." from " 3 PICK EMIT ."  to " 2 PICK EMIT
       [CHAR] . EMIT CR
       DUP 1- >R 1 PICK 3 PICK 5 PICK R> RECURSE
    THEN DROP DROP DROP DROP ;

: TOWER-OF-HANOI ( N -- ) CR >R [CHAR] A [CHAR] C [CHAR] B R> MOVE-DISK ;

: HANOI
  ." How many discs? "
  ENTER TOWER-OF-HANOI
;

HANOI