Finding an item in a binary dictionary.
Source: PROLOG programming for artificial intelligence, 3rd Edition, Harlow, 2001, ISBN 0-201-40375-7.
Program source code: search_tree.pl
% Figure 9.7 Finding an item X in a binary dictionary. % in( X, Tree): X in binary dictionary Tree in( X, t( _, X, _) ). in( X, t( Left, Root, Right) ) :- gt( Root, X), % Root greater than X in( X, Left). % Search left subtree in( X, t( Left, Root, Right) ) :- gt( X, Root), % X greater than Root in( X, Right). % Search right subtree gt(A,B):-A > B.