Syntax question by noob

hr_sea

When using an If - then statement, can I compare against a string?

I'm working on interfacing a Basic Stamp 2 to a laptop by wireless RS-232. I'd like to pass it commands in plain text via Windows Hyperterminal and have the stamp turn pins on and off. I can't seem to only be able to get if-then statements to work with numerical values.

I'm collecting 5 characters or less into "DataIn" array. Appropriate code snippets
SERIN SerialInput,BaudMode,TimeOut,begin,[noparse][[/noparse]SKIP 1, STR DataIn\5\"*"]
IF DataIn ="on" THEN
HIGH 1
ENDIF

Larry~

if datain(0) = "o" and datain(1) = "n" goto turnedon

Mike Green

No

There really are no string values in PBasic. They're treated as special cases in the various I/O statements like SERIN and SEROUT, but they're really considered to be arrays of bytes. None of the expression operators work on arrays.

You can do character comparisons like: IF DataIn(0) = "o" and DataIn(1) = "n" and DataIn(2) = 0 THEN
In this case, you're comparing individual characters and checking that the 'string' ends after two characters. That might be enough for what you want.

hr_sea

Ok, this all makes sense. (why would it be done any other way?). I'll try it out tonight.

Thank you!

RiJoRi

Of course, you may want to imitate C, which also has no strings (at least K&R doesn't). They use library functions to manipulate character arrays -- strcmp, strlen, strcpy, etc. Because C has pointers, it's a little more general than BASIC, but it can be done.

--Rich