Turbo Prolog

Program 7 is a complete Turbo Prolog program that functions as a mini telephone
directory that uses the standard predicates readln and write. The domains section has
been omitted, since only standard domains are used. The program asks for a name to
be typed in. When the name is entered, the corresponding telephone number is found
from the database and displayed on the screen.
1* Program 7 *1
predicates
reference(symbol,symbol)
goal
write(IIPlease type a name :11),
readln(The_Name),
reference(The_Name,Phone_No),
write (liThe phone number is II, Phone_No) , nl.
clauses
reference(IIAlbertll , 1101-1231;56 11 ).
reference(IIBettyll, 1101-569767 11 ).
reference(IICarolll , 1101-2671;00 11 ).
reference(IIDorothyll,1I01-191051 11 ).
Finally, to illustrate the char domain type, Program 8 defines is/etter which, when given
the goals
isletter( '%').
isletter( 'Q').
will return false and true respectively.
1* Program 8 *1
predicates
isletter(char)
clauses
isletter(Ch) if Ch (= 'z' and 'a' (= Ch.
isletter(Ch) if Ch (= 'Z' and 'A' (= Ch.
Exercise Type in Program 7 and try each of these goals in turn.
(1) reference (IiCarol ll , y) .
(2) reference(X,1I01-191951 11 ).
(3) reference(IIMavisll,y).
(1;) reference(X,y).
Kim shares a flat with Dorothy and so has the same phone number. Add this information
to the clauses for the predicate reference and try the goal
reference(X,1I01-191051 11 ).
to check your addition.
Type Program 8 and try each of these goals in turn.
(1) isletter('x').
(2) isletter('2').
(3) isletter(lIhello ll ).
(1;) isletter(a).
(5) isletter(X).
Tutorial II: A Closer Look at Domains, Objects and Lists 37