Write two clauses in Prolog that determines if there are exactly two values in a

Question

Write two clauses in Prolog that determines if there are exactly two values in a list such that they sum a value N. The output should be a single true if there exists two values whose sum is N or a single false if there are not. If there are multiple values whose sum is N then your program should only print true once.

Sample

                List [1, 3, 5, 7] with N equal to 10 should print true. 7 + 3 = 10.

                List [1, 3, 5, 7] with N equal to 20 should print false. No two values sum is 20.

                List [7, 1, 10, 3, 8, 2] with N equal to 9 should print true. 2 + 7 = 9 and 8 + 1 = 9 and 1 + 8 = 9 and 7 + 2 = 9.

Restrictions

You are restricted to the following.

·         Use of at most 2 clauses.

·         +

·         ,

·         ;

·         .

·         !

·         :-

·         is

·         Lists

·         Head and tail syntax for list types

·         Variables

Explanation / Answer

Answer::

list=integer*

findsum(list)
sum(list,integer)

  
clauses

findsum(L):-
sum(L,Sum),
write(" Sum Of Given List : ",Sum).
  
sum([],0).
  
sum([X|Tail],Sum):-
sum(Tail,Temp),
Sum=Temp+X.
  

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.