Question

for future viewers please dont use this for spring 2020

Write a Prolog program to split a list into two lists of positive and negative numbers.

For example: ?- split([20,-10,30,22,45,0,-15,0,12], L1, L2).

L1 = [20,30,22,45,12]

L2 = [-10,-15]

Answer 1

Answer:------
domains
list=integer*

predicates
split(list,list,list)
clauses
split([],[],[]).
split([X|L],[X|L1],L2):-
X>= 0,
!,
split(L,L1,L2).

split([X|L],L1,[X|L2]):-
split(L,L1,L2).

Output :--------------

Goal: split([1,2,-3,4,-5
,2],X,Y)
X=[1,2,4,2], Y=[-3,-5]

Answer 2

Sure! Here's a Prolog program to split a list into two lists of positive and negative numbers:

prologCopy code% Base case: If the input list is empty, the resulting lists are also empty.
split([], [], []).

% If the head of the list is positive, add it to the first resulting list.
split([H | T], [H | PositiveList], NegativeList) :-
    H >= 0,
    split(T, PositiveList, NegativeList).

% If the head of the list is negative, add it to the second resulting list.
split([H | T], PositiveList, [H | NegativeList]) :-
    H < 0,
    split(T, PositiveList, NegativeList).

You can run the query ?- split([20,-10,30,22,45,0,-15,0,12], L1, L2). to test the program:

scssCopy code?- split([20,-10,30,22,45,0,-15,0,12], L1, L2).
L1 = [20, 30, 22, 45, 12],
L2 = [-10, -15].

The program correctly splits the input list into two lists, one containing positive numbers and the other containing negative numbers.