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PROLOG PROGRAMS - Complete Solutions

1. FAMILY TREE IMPLEMENTATION

parent(john, mary).
parent(john, tom).
parent(john, ann).
parent(susan, mary).
parent(susan, tom).
parent(susan, ann).
parent(mary, alice).
parent(mary, bob).
parent(tom, charlie).
parent(tom, diana).
parent(ann, edward).

male(john).
male(tom).
male(bob).
male(charlie).
male(edward).
female(susan).
female(mary).
female(ann).
female(alice).
female(diana).

father(X, Y) :- parent(X, Y), male(X).
mother(X, Y) :- parent(X, Y), female(X).

child(X, Y) :- parent(Y, X).

son(X, Y) :- child(X, Y), male(X).
daughter(X, Y) :- child(X, Y), female(X).

sibling(X, Y) :- parent(Z, X), parent(Z, Y), X \= Y.
brother(X, Y) :- sibling(X, Y), male(X).
sister(X, Y) :- sibling(X, Y), female(X).

grandparent(X, Y) :- parent(X, Z), parent(Z, Y).
grandfather(X, Y) :- grandparent(X, Y), male(X).
grandmother(X, Y) :- grandparent(X, Y), female(X).

grandchild(X, Y) :- grandparent(Y, X).
grandson(X, Y) :- grandchild(X, Y), male(X).
granddaughter(X, Y) :- grandchild(X, Y), female(X).

uncle(X, Y) :- brother(X, Z), parent(Z, Y).
aunt(X, Y) :- sister(X, Z), parent(Z, Y).

cousin(X, Y) :- parent(Z, X), parent(W, Y), sibling(Z, W).

ancestor(X, Y) :- parent(X, Y).
ancestor(X, Y) :- parent(X, Z), ancestor(Z, Y).

descendant(X, Y) :- ancestor(Y, X).

2. LIST CONCATENATION

conc([], L2, L2).
conc([H|T1], L2, [H|T3]) :- conc(T1, L2, T3).

3. LIST REVERSAL

reverse_list(L, R):-
    rev(L,[],R).
rev([], Acc, Acc).
rev([H|T],Acc, R) :-
    rev(T, [H|Acc], R).

4. SUM OF TWO NUMBERS

sum(X, Y, Sum) :- Sum is X + Y.

5. MAXIMUM OF TWO NUMBERS

max(X, Y, X) :- X >= Y.
max(X, Y, Y) :- Y > X.

6. FACTORIAL

factorial(0, 1).
factorial(N, F) :- 
    N > 0,
    N1 is N - 1,
    factorial(N1, F1),
    F is N * F1.

7. FIBONACCI SERIES

generate_fib(0, 0).
generate_fib(1, 1).
generate_fib(N, T) :-
    N > 1,
    N1 is N - 1,
    N2 is N - 2,
    generate_fib(N1, T1),
    generate_fib(N2, T2),
    T is T1 + T2.

8. POWER FUNCTION

power(_, 0, 1).

power(Num, Pow, Ans) :-
    Pow > 0,
    Pow1 is Pow - 1,
    power(Num, Pow1, Ans1),
    Ans is Num * Ans1.

power(Num, Pow, Ans) :-
    Pow < 0,
    PosPow is -Pow,
    power(Num, PosPow, TempAns),
    Ans is 1 / TempAns.

9. MULTIPLICATION

multi(N1, N2, R) :- R is N1 * N2.

10. MEMBERSHIP CHECK

memb(X, [X|_]).
memb(X, [_|T]) :- memb(X, T).

11. SUM OF LIST - sumlist(L, S)

sumlist([], 0).

sumlist([H|T], S) :-
    sumlist(T, S1),
    S is H + S1.

12. EVEN/ODD LENGTH

evenlength([]).
evenlength([_|T]) :- oddlength(T).

oddlength([_]).
oddlength([_|T]) :- evenlength(T).

13. MAXIMUM IN LIST

max(X, Y, X) :- X >= Y.
max(X, Y, Y) :- Y > X.
maxlist([X], X).
maxlist([H|T], M) :-
    maxlist(T, M1),
    max(H, M1, M).

14. INSERT AT POSITION

insert(I, 1, L, [I|L]).
insert(I, N, [H|T], [H|R]) :-
    N > 1,
    N1 is N - 1,
    insert(I, N1, T, R).

15. DELETE AT POSITION

delete(1, [_|T], T).
delete(N, [H|T], [H|R]) :-
    N > 1,
    N1 is N - 1,
    delete(N1, T, R).
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