Re: Users-prolog Digest, Vol 79, Issue 2
Duncan Patton a Campbell <[email protected]>
| Newsgroups | gmane.comp.gnu.prolog.general |
|---|---|
| Organization | NeoText |
| Message-ID | <[email protected]> |
On Fri, 18 Dec 2009 12:00:25 -0500 [email protected] wrote: > > James Gale wrote: ... I assuming you want a function that tests whether a number is even or odd? Such a function is not built into Gprolog, so you will need to construct one. exempli gratia: With a text editor (vi on *nix, notepad on Wondiws) load edit a file, called myeven.pl and enter the following line: even_number(N) :- 0 is N /\ 1. Save the file and start the prolog interpreter in the directory containing myeven.pl gprolog GNU Prolog 1.3.1 By Daniel Diaz Copyright (C) 1999-2009 Daniel Diaz | ?- [myeven]. compiling /tmp/myeven.pl for byte code... /tmp/myeven.pl compiled, 2 lines read - 366 bytes written, 22 ms yes | ?- At this point we have loaded the code in myeven.pl into the interpreter and you can test it so: | ?- even_number(22). yes | ?- even_number(22). yes | ?- even_number(-22). yes | ?- even_number(3). no | ?- even_number(-223). no | ?- even_number(-223.0). uncaught exception: error(type_error(integer,-223.0),(is)/2) | ?- This last error is because our one line function is factored to only deal with integers. I hope this helps. Dhu