prolog

问题 how can I do the following. I needed to define the predicate shownumber (X,N) , which is true when the symbol X corresponds to the natural number N. For example, shownumber(s(zero),1) is true. Okay, now I've got a predicate: shownumber (zero, 0). shownumber (s (N), X): - shownumber (N, Y), X is Y + 1. Now I need to use the shownumber (X, Y) predicate to define: 1) times (X, Y, Z) which is true if X * Y = Z. 2) quotient (X, Y, Q) which is true if X / Y = Q (in natural number arithmetic) 3)

问题 I'm trying to split a list into the items before a specific element (specifically the word "stop") as well as the items after this element. I know you can use split to do this, but I'm new to prolog and so I'm trying to manipulate things without using these functions currently, and so I'd really like to know if this is possible? (and maybe some pointers in the right direction) i.e. with the list; L = [tea,coffee,sugar,cake,stop,meat,fish,eggs,flour] I'd ideally want to split the list at 'stop

问题 How would I be able to obtain the totalcost and loop through each employee to get the cost individually? Expected output: ?- make_team([batman, superman, aquaman], Heroes, TotalCost). Heroes = [[batman, bruce, wayne, 342000], [superman, clark, kent, 475000], [aquaman, arthur, curry, 5000]], TotalCost = 822000. % Returns a list of available heroes. % Each hero's information is also stored as a list. employees(E) :- E = [ [superman, clark, kent, 475000], [batman, bruce, wayne, 342000], [wonder

问题 Suppose you have a database with the following content: son(a, d). son(b, d). son(a, c). son(b, c). So a and b are sons of d and c. Now you want to know, given a bigger database, who is brother to who. A solution would be: brother(X, Y) :- son(X, P), son(Y, P), X \= Y. The problem with this is that if you ask "brother(X, Y)." and start pressing ";" you'll get redundant results like: X = a, Y = b; X = b, Y = a; X = a, Y = b; X = b, Y = a; I can understand why I get these results but I am

问题 How to convert float to integer in prolog? I tried: ?- integer(truncate(sqrt(9))). false. ?- integer(round(sqrt(9))). false. 回答1: The predicate integer/1 that you used is true iff its argument is an integer. Since the term truncate(sqrt(9)) is not an integer, the predicate does not hold and therefore fails for this term. There are at least two ways to get what you want: Solution 1: Quick and broken You can use the predicate (is)/2 for conversion between different number representations. In

问题 I am trying to write a predicate that ‘exists’ inside the ‘scope’ of another predicate . The reason I need this is because both predicates make use of the same very large parameters/arrays and the predicate I want to nest is doing self recurssion many times , so I want to avoid copying the same parameters . So , is there any way i can do this in Swi-Prolg ? Thanks in advance . 回答1: You don't need to. You have to realize that all the terms "named" by Prolog variable names are already global ,

问题 I'm new to PROLOG and am at the very beginning of the exercises on this page. Given the rules parent(X, Y) and male(X), I'm trying to define a rule mother(X, Y) as mother(X, Y) :- not(male(X)), parent(X, Y). However, in GNU Prolog I get the following error: | ?- mother(lina, julia). uncaught exception: error(existence_error(procedure,not/1),mother/2) | ?- 回答1: \+/1 is the ISO Prolog predicate to "negate". Note that "negate" means here not provable at that point. You can refer to this

问题 I'm new to PROLOG and am at the very beginning of the exercises on this page. Given the rules parent(X, Y) and male(X), I'm trying to define a rule mother(X, Y) as mother(X, Y) :- not(male(X)), parent(X, Y). However, in GNU Prolog I get the following error: | ?- mother(lina, julia). uncaught exception: error(existence_error(procedure,not/1),mother/2) | ?- 回答1: \+/1 is the ISO Prolog predicate to "negate". Note that "negate" means here not provable at that point. You can refer to this

问题 I'm new to PROLOG and am at the very beginning of the exercises on this page. Given the rules parent(X, Y) and male(X), I'm trying to define a rule mother(X, Y) as mother(X, Y) :- not(male(X)), parent(X, Y). However, in GNU Prolog I get the following error: | ?- mother(lina, julia). uncaught exception: error(existence_error(procedure,not/1),mother/2) | ?- 回答1: \+/1 is the ISO Prolog predicate to "negate". Note that "negate" means here not provable at that point. You can refer to this

问题 I implemented the following power program in Prolog: puissance(_,0,1). puissance(X,N,P) :- N>0,A is N-1, puissance(X,A,Z), P is Z*X. The code does what is supposed to do, but after the right answer it prints "false.". I don't understand why. I am using swi-prolog. 回答1: You can add a cut operator (i.e. ! ) to your solution, meaning prolog should not attempt to backtrack and find any more solutions after the first successful unification that has reached that point. (i.e. you're pruning the