reverse_list
reverse_list
(OP)
Hi, I don't understand how this programm works.
reverse_list([], []).
reverse_list([Head | Tail], ReversedList) :-
reverse_list(Tail, ReversedTail),
append(ReversedTail, [Head], ReversedList).
It is assumed to reverse a list, but I don't know what calls does it make and with what order. Can anyone help me? I tried to run it on Swi-Prolog, but it didn' t help me. Thank you.
reverse_list([], []).
reverse_list([Head | Tail], ReversedList) :-
reverse_list(Tail, ReversedTail),
append(ReversedTail, [Head], ReversedList).
It is assumed to reverse a list, but I don't know what calls does it make and with what order. Can anyone help me? I tried to run it on Swi-Prolog, but it didn' t help me. Thank you.
Talk To Other Members
RE: reverse_list
?- guitracer.
at the Prolog prompt. Then type this:
?- trace, reverse_list([5]).
?- trace, reverse_list([5, 6]).
?- trace, reverse_list([5, 6, 7]).
If you understand reversal of 1-element lists, it would be easier to understand reversal of 2-element lists, then 3-element lists and then N-element lists. It's recursivity.
In case you don't have experience with debugging, the green line shows where execution is, and somewhere in the upper left part of the debug window you'll see all the variables involved. To move one step forward with the execution, press SPACE and watch closely how variables are affected.
RE: reverse_list
RE: reverse_list
RE: reverse_list
Type these instead:
?- trace, reverse_list([5], Result).
?- trace, reverse_list([5, 6], Result).
?- trace, reverse_list([5, 6, 7], Result).
RE: reverse_list