On Gosub?

[MrVertigo]

The ZX81 doesn’t have the ON GOSUB option. I’ve read that a solution to this is to set up a calculation in a GOSUB line. Is this the BEST way to achieve what ON GOSUB does in other versions of BASIC?

E.G: Instead of
100 ON X GOSUB 500,640,780 etc

Use:

100 590*(X=1)+640*(x=2)+780*(x=3) etc

( Is it also true that the Spectrum doesn’t have ON GOSUB?)

[1024MAK]

ON GOTO and ON GOSUB is not included in the BASIC for any of the ZX80, ZX81 or ZX Spectrum computers.

For the ZX81 and ZX Spectrum use a computed GOTO or GOSUB.

For example:

Code: Select all

10 PRINT “ENTER AGE”
20 INPUT A
30 IF A<=0 OR A>115 THEN GOTO 20
40 LET A=INT A
50 GOSUB A*10+1000
60 GOTO 10
1120 PRINT “A CHILD”
1121 RETURN
1190 PRINT “A TEENAGER, REALLY?”
1191 RETURN
1290 PRINT “A YOUNG ADULT”
1291 RETURN
1490 PRINT “APPROACHING MID-LIFE THEN…”
1491 RETURN
2150 PRINT “HELLO OLD FART”
2151 RETURN

Mark

[MrVertigo]

Nice!