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pl:prolog:pllib:geometric_objects [2019/06/27 15:50] |
pl:prolog:pllib:geometric_objects [2019/06/27 15:50] (aktualna) |
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| + | ====== Geometric objects ====== | ||
| + | {{tag>geometry OOP}} | ||
| + | ===== Description ===== | ||
| + | An object-oriented program about geometric figures. | ||
| + | |||
| + | **Source**: PROLOG programming for artificial intelligence, 3rd Edition, Harlow, 2001, ISBN 0-201-40375-7. | ||
| + | ===== Download ===== | ||
| + | Program source code: {{geometric_objects.pl}} | ||
| + | ===== Listing ===== | ||
| + | <code prolog> | ||
| + | % Figure 23.6 An object-oriented program about geometric figures. | ||
| + | |||
| + | |||
| + | /* polygon( [Side1, Side2, ...]) | ||
| + | / \ | ||
| + | / \ | ||
| + | rectangle( Length, Width) reg_polygon( Side, N) | ||
| + | \ / \ | ||
| + | \ / \ | ||
| + | square( Side) pentagon( Side) | ||
| + | */ | ||
| + | |||
| + | object( polygon( Sides), | ||
| + | [ ( perimeter( P) :- | ||
| + | sum( Sides, P) ) ] ). | ||
| + | |||
| + | object( reg_polygon( Side, N), | ||
| + | [ ( perimeter( P) :- | ||
| + | P is Side * N), | ||
| + | ( describe :- write( 'Regular polygon') ) ] ). | ||
| + | |||
| + | object( square( Side), | ||
| + | [ ( describe :- | ||
| + | write( 'Square with side '), | ||
| + | write( Side) ) ] ). | ||
| + | |||
| + | object( rectangle( Length, Width), | ||
| + | [ ( area( A) :- | ||
| + | A is Length * Width), | ||
| + | ( describe :- | ||
| + | write( 'Rectangle of size '), | ||
| + | write( Length * Width) ) ] ). | ||
| + | |||
| + | object( pentagon( Side), | ||
| + | [ ( describe :- write( 'Pentagon') ) ] ). | ||
| + | |||
| + | isa( square( Side), rectangle( Side, Side)). | ||
| + | |||
| + | isa( square( Side), reg_polygon( Side, 4)). | ||
| + | |||
| + | isa( rectangle( Length, Width), polygon( [Length,Width,Length,Width])). | ||
| + | |||
| + | isa( pentagon( Side), reg_polygon( Side, 5)). | ||
| + | |||
| + | isa( reg_polygon( Side, N), polygon( L)) :- | ||
| + | makelist( Side, N, L). | ||
| + | |||
| + | % makelist( Item, N, List) if | ||
| + | % List is the list in which Item appears N times | ||
| + | |||
| + | makelist( _, 0, []). | ||
| + | |||
| + | makelist( Item, N, [Item | List]) :- | ||
| + | N > 0, N1 is N - 1, | ||
| + | makelist( Item, N1, List). | ||
| + | |||
| + | % sum( ListOfNumbers, Sum) if | ||
| + | % Sum is the sum of numbers in ListOfNumbers | ||
| + | |||
| + | sum( [], 0). | ||
| + | |||
| + | sum( [Number | Numbers], Sum) :- | ||
| + | sum( Numbers, Sum1), | ||
| + | Sum is Sum1 + Number. | ||
| + | </code> | ||
| + | ===== Comments ===== | ||
