Maze generation: Difference between revisions

<lang rexx>/*REXX program generates and displays a rectangular solvable maze (of any size). */

height=0; @.=0 /*default for all cells visited. */

parse arg rows cols seed . /*allow user to specify the maze size. */

if rows='' | rows=='",'" then rows=19 /*No rows given? Then use the default.*/

if cols='' | cols=='",'" then cols=19 /* " cols " ? " " " " */

if seed\=='' then call random ,,seed /*use a random seed for repeatability.*/

call buildRow '┌'copies('"─┬'", cols-1)'─┐' /*buildconstruct the top edge of the maze. */

/* [↓] construct the maze's grid. */

do r=1 for rows; _=; __=; hp= "|"; hp= '|'; hj='├'

do c=1 for cols; _= _||hp'1'; __=__||hj'"─'"; hj='┼'; hp='"│'"

call buildRow _'│' /*buildconstruct the right edge of cells.the cells*/

if r\==rows then call buildRow __'┤' /* " " " " " " maze. */

call buildRow '└'copies('"─┴'", cols-1)'─┘' /*construct the bottom maze edge. of the maze*/

r!=random(1,rows)*2; c!=random(1,cols)*2; @.r!.c!=0 /*choose the 1stfirst cell.*/

/* [↓] traipse through the maze. */

do forever; n=hood(r!, c!); if n==0 then if \fCell() then/*number of free maze cells. leave*/

callif ?;n==0 then if \fCell() @._r._c=0 then leave /*getif theno (next)free maze directioncells toleft, go.then done*/

ro=r!;call co=c!?; r!=_r; c!= @._r._c=0 /*saveget the original(next) cellmaze coordinates.direction to go. */

?.zrro=?.zr%2r!; ?.zc co=?.zc%2c!; r!=_r; c!=_c /*getsave the maze row andoriginal cell directionscoordinates. */

rw?.zr=ro+?.zr%2; cw ?.zc=co+?.zc%2 /*calculateget the next maze row and col.cell directions.*/

@.rw.cw=ro+?.zr; cw=co+?.zc /*markcalculate the mazenext cellmaze asrow beingand visitedcol. */

do r=1 for height; _= /*display the maze. */

if \(r//2) then _=translate(_, '\', .) /*trans to backslash*/

_=changestr(1 , _, 111) /*──────these four ────────────────────*/

_=changestr(0 , _, 000) /*───────── statements are ────────────*/

_=changestr( . , _, " ") /*────────────── used for preserving ──*/

_=changestr('─', _, "───") /*────────────────── the aspect ratio. */

say translate(_, '│', "|\10") /*make it presentable for the screen. */

exit /*stick a fork in it, we're all done. */

@: parse arg _r,_c; return @._r._c /*a fast way to reference a maze cell. */

?: do forever; ?.=0; ?=random(1,4); if ?==1 then ?.zc=-2 /*north*/

if ?==2 then ?.zr= 2 /* east*/

if ?==3 then ?.zc= 2 /*south*/

if ?==4 then ?.zr=-2 /* west*/

_r=r!+?.zr; _c=c!+?.zc; if @._r._c==1 then return

end /*forever*/

buildRow: parse arg z; height=height+1; width=length(z)

do c=1 for width; @.height.c=substr(z,c,1); end; return

fCell: do r=1 for rows; rr=r+r

do c=1 for cols; cc=c+c

if hood(rr,cc)==1 then do; r!=rr; c!=cc; @.r!.c!=0; return 1; end

end /*c*/

end /*r*/ /* [↑] r! &and c! are used by invoker.*/

return 0

hood: parse arg rh,ch; return @(rh+2,ch) + @(rh-2,ch) + @(rh,ch-2) + @(rh,ch+2)</lang>