====== Interface ======
{{tag>interactive}}
===== Description =====
The simplest version of ask prompts the user with the requested attribute and value and seeks confirmation or denial of the proposed information.

**Source**:  Building Expert Systems in PROLOG Publisher
===== Download =====
Program source code: {{interface.pl}}
===== Listing =====
<code prolog>
ask(Attr, Val):-
write(Attr:Val),
write('? '),
read(yes).

eats(X):- ask(eats, X).

feet(X):- ask(feet, X).

wings(X):- ask(wings, X).

neck(X):- ask(neck, X).

color(X):- ask(color, X).
</code>
===== Comments =====