Route Finding

From: Joe_Baker (poppa_baker_at_nospamhotmail.com)
Date: 05/05/04 

Date: Wed, 05 May 2004 11:31:47 -0400

Hi, I am wrote a program to find a route between two places, like this:

link(a, b).
link(b, c).
etc..

route(From, To):-
        link(From, To)

route(From, To):-
        link(From, Via),
        route(Via, To).

This works fine, I then tried to modify it by outputting the route
followed.
My attempt was.

link(a, b).
link(b, c).
link(c, d).
etc...

route(From, To):-
        route(From, To, From).

route(From, To, Route):-
        link(From, To),
        print_route([To|Route]).

route(From, To, Route):-
        link(From, Via),
        route(Via, To, [Via|Route]).

print_route([]).

print_route([Head|Tail]):-
        write(Head),
        write(' '),
        print_route(Tail).

The result of any query is always no, and a list is written, which does
not seem to make much sense!

If anyone could help i would be very grateful!
Joe

Relevant Pages

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