Rosetta Code

Towers of Hanoi: Difference between revisions

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Towers of Hanoi (view source)

Revision as of 18:56, 6 September 2015

177 bytes removed ,  8 years ago
m
→‎pictorial moves: added/changed whitespace and comments, elided some dead code, broke apart a long line of assignments, changed the wording in the REXX section header.
m (→‎simple text moves: added/changed whitespace and comments, changed the wording of the output.)
m (→‎pictorial moves: added/changed whitespace and comments, elided some dead code, broke apart a long line of assignments, changed the wording in the REXX section header.)
Line 2,561:
 
===pictorial moves===
This REXX version pictorially shows the moves for solving the Town of Hanoi.
 
Quite a bit of code has been dedicated to showing a "picture" of the towers with the disks, and the movement of the disk (thefor each move).   "Coloring" of the ringsdisks is attempted with dithering.
 
In addition, it shows each move in a countdown manner (the last move is marked as #1).
 
No attempt is made to explain this version of the REXX program 'cause of the complexity and somewhat obtuse features of the REXX language, the smallest of which is support for ASCII and EBCDIC "graphic" characters (glyphs).   It may not be obvious from the pictorial display of the moves, but whenever a ringdisk is moved from one tower to another, it is always the top ringdisk that is moved   (to the target tower).
<lang rexx>/*REXX program shows pictorial moves to solve Tower of Hanoi (with N towersdisks).*/
parse arg N .; if N=='' then N=3 /*Not given? Then use default 3 disks.*/
sw=80; wp=sw%3-1; blanks=left('',wp) /*define some default REXX variables. */
Line 2,576:
#=0; z=2**N-1; moveK=z /*#moves; min# of moves; where to move.*/
@abc='abcdefghijklmnopqrstuvwxyN' /*dithering chars when many disks used.*/
ebcdic= ('f0'x==0) /*determine if EBCDIC or ASCII machine.*/
 
if ebcdic then do; bar='bf'x; ar="df"x; boxen='db9f9caf'x; down="9a"x
bar='bf'x;ar='df'x;boxen='db9f9caf'x;tl='ac'x; tr='bfbc'x; bl='"ab'"x; br='bb'x; vert='"fa'"x;down tl='9aac'x
end
else do; bar='c4'x; ar="10"x; boxen='b0b1b2db'x; down="18"x
bar='c4'x;ar='10'x;boxen='b0b1b2db'x;tl='da'x; tr='bf'x; bl='"c0'"x; br='d9'x; vert='"b3'"x;down tl='19da'x
end
 
verts = vert || vert; Tcorners= tl || tr
downs = down || down; Bcorners= bl || br
box = left(boxen,1); boxcharsboxChars= boxen || @abc; bararrow= bar || bar || ar
$.=0; $.1=N; k=N; kk=k+k
 
do j=1 for N; @.3.j=blanks; @.2.j=blanks; @.1.j=center(copies(box,kk),wp)
if N<=length(boxcharsboxChars) then @.1.j=translate(@.1.j,,substr(boxcharsboxChars,kk%2,1),box)▼
@.1.j=center(copies(box,kk),wp)
▲ if N<=length(boxchars) then @.1.j=translate(@.1.j,,substr(boxchars,kk%2,1),box)
kk=kk-2
end /*j*/ /*populate the pp=pptower ||of trHanoi spindles.*/▼
end /*j*/
 
call showtowers; call mov 1,3,N; say
say "'The minimum number of moves to solve a "' N"-disk ' Tower of Hanoi is '" z▼
say
▲say "The minimum number of moves to solve a " N ' Tower of Hanoi is ' z
exit
/*─────────────────────────────MOV subroutine─────────────────────────────────*/
mov: if arg(3)==1 then call rngdsk arg(1) arg(2)
else do; call mov arg(1), 6-arg(1)-arg(2), arg(3)-1
call mov arg(1), 6-arg(1)- arg(2), arg(3)- 1
call mov 6-arg(1)-arg(2), arg(2), arg(3)-1
call mov 6-arg(1)-arg(2),arg(2), arg(3)-1
end
return
/*─────────────────────────────RNG─────────────────────────────DSK subroutine─────────────────────────────────*/
rngdsk: parse arg from dest; #=#+1; pp=
if from==1 then do
pp=overlay(bl, pp, c.1)
pp=overlay(bar, pp, c.1+1, c.dest-c.1-1, bar) || tr
pp=pp || tr
end
if from==2 then do
lpost=min(2, dest)
hpost=max(2, dest)
if dest==1 then do
pp=overlay(tl, pp, c.1)
pp=overlay(bar, pp, c.1+1, c.2-c.1-1, bar)||br
pp=pp || brend
if dest==3 then enddo
if dest= pp=3overlay(bl, then dopp,c.2)
pp=overlay(blbar, pp,c.2+1, c.3-c.2-1, bar) ||tr
pp=overlay(bar,pp,c.2+1,c.3-c.2-1,bar) end
▲ pp=pp || tr
end
end
if from==3 then do
pp=overlay(br, pp, c.3)
pp=overlay(bar, pp, c.dest+1, c.3-c.dest-1, bar)
pp=overlay(tl, pp, c.dest)
end
say translate(pp, downs, Bcorners || Tcorners || bar); say overlay(moveK,pp,1)
say translate(pp, verts, Tcorners || Bcorners || bar)
say translate(pp, downs, Tcorners || Bcorners || bar); moveK=moveK-1
$.from=$.from-1; $.dest=$.dest+1; _f=$.from+1; _t=$.dest
moveK=moveK-1
$@.fromdest._t=$@.from-1._f; $@.dest=$from.dest+1; _f=$.from+1blanks; call _t=$.destshowtowers
@.dest._t=@.from._f; @.from._f=blanks
call showtowers
return
/*─────────────────────────────SHOWTOWERS subroutine──────────────────────────*/
showtowers: do j=N by -1 for N; _=@.1.j @.2.j @.3.j; if _\='' then say _; end
end /*j*return</lang>
'''output''' &nbsp; when using the default input:
return</lang>
{{out}}when the default input was used:
<pre>
░░
Line 2,693 ⟶ 2,684:
▓▓▓▓▓▓
 
The minimum number of moves to solve a 3-disk Tower of Hanoi is 7
</pre>
 
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