Page 1 of 1

PI or not PI, that is the question.

Posted: Mon Jan 22, 2018 12:56 am
by Shaun_B
Hi,

I've noticed that on ZX81 BASIC, I can use PI as a variable name (not the token PI), like this:

Code: Select all

     1 LET PI=3.14
     2 PRINT PI
However, I can't use PI in a FOR loop, like:

Code: Select all

     1 FOR PI=0 TO 3
     2 PRINT PI
     3 NEXT PI
Is this a limitation of the FOR command (i.e., can you only use single-character variable names in FOR loops)?

Thanks,

Shaun.

Re: PI or not PI, that is the question.

Posted: Mon Jan 22, 2018 1:03 am
by rcade
Loop variables can only be one character.

Re: PI or not PI, that is the question.

Posted: Mon Jan 22, 2018 9:53 am
by siggi
Variables can also contain SPACES:

Code: Select all

10 LET NOT PI = 0
20 PRINT NOT PI
:mrgreen:

Re: PI or not PI, that is the question.

Posted: Mon Jan 22, 2018 10:29 pm
by PokeMon
There is a distinction between keywords and plain letters.
So PI is not PI (P and I).
Also this is valid :lol:

Code: Select all

10 LET LET=99
20 PRINT LET
30 LET PRINT=88
40 PRINT PRINT

I guess this is handled wrong with the ZX-IDE but this unusual programming style ... ;)

Re: PI or not PI, that is the question.

Posted: Wed Jan 24, 2018 10:11 pm
by Shaun_B
You can also do this:

Code: Select all

     1 LET APPLE PI = 3.14
     2 PRINT APPLEPI
Regards,

Shaun.

Re: PI or not PI, that is the question.

Posted: Mon Jan 29, 2018 3:35 am
by gammaray
That is just so wrong!

Re: PI or not PI, that is the question.

Posted: Mon Jan 29, 2018 9:49 am
by siggi
Re: PI or not PI, that is the question.
The real question is

Code: Select all

10 if two beer or not two beer ....
:mrgreen:
Siggi