AltairClone.com

Here is a little program I originally wrote back in the late 80's on VAX BASIC.

It a solution to the Towers of Hanoi for an arbitrary number of disks that utilizes the concept of recursion. The solution it generates is the absolute minimum number of moves for a given number of disks. It was a little different when written in VAX BASIC because VAX BASIC supports local data spaces for subroutines and hence allows for true recursion. I re-wrote it for MBASIC and implemented the recursion through using a temporary variable and shifting values around before and after the recursive calls (to line 190).

In the following code T is the temporary variable. S is the source tower, D is the destination tower. See if you can figure out how it works.. and have some fun.

Code: Select all

10 FOR X=0 TO 20:PRINT:NEXT X
20 PRINT "*********************"
30 PRINT "*                   *"
40 PRINT "*  TOWERS OF HANOI  *"
50 PRINT "*                   *"
60 PRINT "*********************"
70 PRINT
75 K=0
80 INPUT "NUMBER OF DISKS";J
90 S=1:B=2:D=3:N=J+1
100 GOSUB 190
105 PRINT K;" MOVES REQUIRED"
110 END
190 N=N-1
200 IF N=1 THEN GOSUB 300:GOTO 240
210 T=B:B=D:D=T:GOSUB 190:T=D:D=B:B=T:N=N+1
220 GOSUB 300
230 T=S:S=B:B=T:GOSUB 190:T=B:B=S:S=T:N=N+1
240 RETURN
300 PRINT "MOVE";S;"TO";D;
305 K=K+1
315 PRINT
320 RETURN


Cool! I used to love writing recursive programs to solve puzzle games.

That's very cool, Bill. I'm anxious to run it, as well as the other "Hanoi-2" version you uploaded recently.

Speaking of VAX BASIC, find below an archive of BASIC programs. They're mostly David Ahl's 1970s programs (which is why I referenced VAX BASIC) but I modified them to run using Microsoft 8K BASIC. I tested all of them on a Synertek System's Sym-1, which is a 6502 machine from the 1970s. It's a lot like the KIM-1. The 8K BASIC for the 6502 had no trig functions, so a few programs have a call to a machine-language patch that provides trig. Those can be commented out when running on the Altair. But other than that, they should all run. I've tested a few of them on my Altair clone like Conway's Life program, Buzzwords, Poetry, Eliza, etc.

• BASIC_Programs.zip

  BASIC Programs

  (1.8 MiB) Downloaded 211 times

I've played around with the C compiler, but haven't done much beyond "Hello World" kind of stuff. I had hoped to port some C code that runs on my Sym-1, but the K&R compiler on the Altair is just a little too old. I didn't use many modern constructs in the Sym-1 code - after all, it's a 6502 and it's pure C code - but it does use some ANSI C functions and that's not far enough back on the Wayback Machine. So I need to roll my sleeves up and look into that a little more later.

Beyond that, I'm putting together an 8800c, with parts from Mike. So after a few weeks or a month or two, I should be able to save and load files on floppy, just like the good 'ol days.

Thanks Wayne. It should be fun going through those!