Screen showing execution of maze program
Amazing program from BASIC Computer Games
The maze program is one of the games in the famous BASIC Computer Games published in 1978. In the book it is called 'Amazing' and the code available in Vintage BASIC. I have rewritten it in COMAL-80 for the Commodore 64 and cleaned it up.
COMAL-80 edition
0010 DIM visited(25,25) 0020 DIM cells(25,25) 0030 DIM d(10) 0040 0050 // Constants 0060 no_floor:=%00000001 0070 no_right_wall:=%00000010 0080 0090 LOOP 0100 PRINT "WHAT ARE YOUR LENGTH AND WIDTH" 0110 INPUT rows,cols 0120 EXIT WHEN rows>1 AND rows<=25 AND cols>1 AND cols<=25 0130 PRINT "MEANINGLESS DIMENSIONS. TRY AGAIN" 0140 ENDLOOP 0150 totcells:=rows*cols 0160 FOR q:=1 TO rows DO 0170 FOR z:=1 TO cols DO 0180 visited(q,z):=FALSE 0190 cells(q,z):=0 0200 ENDFOR z 0210 ENDFOR q 0220 bottom:=FALSE 0230 entry:=RND(1,cols) 0240 PRINT 0250 // Print top 0260 FOR c:=1 TO cols DO 0270 IF c=entry THEN 0280 PRINT ". ", 0290 ELSE 0300 PRINT ".--", 0310 ENDIF 0320 ENDFOR c 0330 PRINT "." 0340 r:=1 0350 c:=entry 0360 cellinx:=1 0370 visited(r,c):=TRUE 0380 REPEAT 0390 l580: 0400 dx:=0 0410 IF c<>1 THEN 0420 IF visited(r,c-1)=FALSE THEN 0430 dx:=dx+1 0440 d(dx):=1 0450 ENDIF 0460 ENDIF 0470 IF c<>cols THEN 0480 IF visited(r,c+1)=TRUE THEN 0490 GOTO l750 0500 ENDIF 0510 dx:=dx+1 0520 d(dx):=2 0530 ENDIF 0540 IF r>1 THEN 0550 IF visited(r-1,c)=FALSE THEN 0560 dx:=dx+1 0570 d(dx):=3 0580 ENDIF 0590 ENDIF 0600 l750: 0610 IF r<rows THEN 0620 IF visited(r+1,c)=TRUE THEN 0630 GOTO l820 0640 ENDIF 0650 ELSE 0660 IF bottom=TRUE THEN 0670 GOTO l820 0680 ENDIF 0690 ENDIF 0700 dx:=dx+1 0710 d(dx):=4 0720 l820: 0730 IF dx=0 THEN 0740 findvisited 0750 GOTO l580 0760 ENDIF 0770 x:=RND(1,dx) 0780 IF d(x)=4 THEN 0790 cells(r,c):=cells(r,c) BITOR no_floor 0800 r:=r+1 0810 IF r>rows THEN 0820 bottom:=TRUE 0830 r:=1 0840 c:=0 0850 findvisited 0860 GOTO l580 0870 ENDIF 0880 ENDIF 0890 IF d(x)=3 THEN 0900 r:=r-1 0910 cells(r,c):=no_floor 0920 ENDIF 0930 IF d(x)=2 THEN 0940 cells(r,c):=cells(r,c) BITOR no_right_wall 0950 c:=c+1 0960 ENDIF 0970 IF d(x)=1 THEN 0980 c:=c-1 0990 cells(r,c):=no_right_wall 1000 ENDIF 1010 cellinx:=cellinx+1 1020 visited(r,c):=TRUE 1030 UNTIL cellinx>=totcells 1040 // Print maze 1050 FOR r:=1 TO rows DO 1060 PRINT "!", 1070 FOR c:=1 TO cols DO 1080 IF cells(r,c) BITAND no_right_wall=0 THEN 1090 PRINT " !", 1100 ELSE 1110 PRINT " ", 1120 ENDIF 1130 ENDFOR c 1140 PRINT 1150 FOR c:=1 TO cols DO 1160 IF cells(r,c) BITAND no_floor=0 THEN 1170 PRINT ":--", 1180 ELSE 1190 PRINT ": ", 1200 ENDIF 1210 ENDFOR c 1220 PRINT ":" 1230 ENDFOR r 1240 END 1250 1260 PROC findvisited 1270 REPEAT 1280 c:=c+1 1290 IF c>cols THEN 1300 r:=r+1 1310 IF r>rows THEN 1320 r:=1 1330 ENDIF 1340 c:=1 1350 ENDIF 1360 UNTIL visited(r,c)=TRUE 1370 ENDPROC findvisited