Download review questions prolog

AI Midterm Review
Fall 2020/2021
Q1. Which of the following are syntactically correct Prolog objects? If yes, identify
the types of object they are (atom, number, variable, structure). If not, use a “No” as
an answer.
Term
Type
1.
5xyz
No
2.
_
Varible
3.
-3.2
Number
4.
Tfile([a, b, c])
No
5.
+(John, Mary)
Structure
Q2. Show the variable instantiations (the values of X, Y and Z) if the matching
between the term in the first column and the term in the second column succeeds.
Use “No” otherwise.
Term1
Term2
Instantiations
1.
[f(a), f(a)]
[X | Y]
X= f(a), Y= [f(a)]
2.
[f(a), f(a), c]
[X, Y|Z]
X= f(a), Y= f(a), Z = [c]
3.
[g(c), b, c]
[g(X), Y, Z] X =c, Y=b, Z=c
4.
[g(Y), b, f(a)]
[X, Y, Z]
X=g(b), Y=b, Z= f(a)
5.
[a, [e, [d]], c]
[X,Y,Z]
X=a, Y=[e,[d]]. Z= c
6.
[1, 4, 6]
[ _ | [X| [Y]]] X=4, Y=6
7.
[a, b]
[ X | [Y | Z ] ] X=a, Y=b, Z= []
8.
[c, b, d]
[X, a | Y]
no
9.
f(g(Z, a), X)
f(Y, g(b, Z)) Y=g(Z,a), X=g(b,Z)
10.
p(f(X), g(b,
p(f(g(c)), g(X, no
Y))
a))
Q3. Consider the following program:
set_dif([],Y,[]).
set_dif([X|R],Y,Z) :- member(X,Y),set_dif(R,Y,Z),!.
set_dif([X|R],Y,[X|Z]) :- set_dif(R,Y,Z).
What is the output of the following?
? set_dif([1,2,3,4],[3,4,5,6],L).
L= [1,2]
Q4. Suppose you have the following prolog program:
fib(0,0).
fib(1,1).
fib(N,F):- N>1, N1 is N-1,
fib(N1,F1), N2 is N-2,
1
fib(N2, F2), F is F1+F2.
What is the output of the followings?
a) ? fib(-1,N)
no
b) fib(2,N).
N= 1
c) fib(6,N).
N= 8
Q5. Write a Prolog predicate split(List, Odds, Evens) that insert the following.
• Odds contains all the items in the odd positions of List
• Evens contains all the items in the even positions of List
Example: ? split([a,b,c,e,f,g,h],O, E).
O = [a,c,f,h], E = [b,e,g],
split([ ], [ ], [ ]).
split([X], [X],[]).
split([X ,Y |T ],[ X |T1], [Y |T2 ]):split(T ,T1,T2 ).
Q6. Write a prolog Program that read students grades in AI class. Keep reading until
a negative grade is read. Display the average of the class
Your program should display:
The average of the class = ###.##
:- dynamic stat/2.
stat(0,0).
do:write(‘Enter a grade [negative to stop]:’),
read(G),
process(G).
process(G):G < 0,
retract(stat(Sum, Count)),
Average is Sum / Count,
write(‘The average of the class =’),
write(Average), !.
process(G):G >= 0,
retract(stat(Sum, Count)),
Sum1 is Sum + G,
Count1 is Count + 1,
assert(stat(Sum1,Count1)),
nl,
do.
End of Review
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