Singly-linked list/Reversal
Reverse a linked list. Obviously you can do it by turning it into a normal list and back, but feel free to use a smarter, possibly more efficient way.
Singly-linked list/Reversal is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.
- I don't even know how to reverse a linked-list, and I don't even know what that is. -- a YouTuber.
ALGOL 68
Using the code from the Singly-linked list/Traversal#ALGOL_68 Task
BEGIN
MODE STRINGLIST = STRUCT(STRING value, REF STRINGLIST next);
# construct a STRINGLIST wuth a few elments #
STRINGLIST list := ("Big",
LOC STRINGLIST := ("fjords",
LOC STRINGLIST := ("vex",
LOC STRINGLIST := ("quick",
LOC STRINGLIST := ("waltz",
LOC STRINGLIST := ("nymph",NIL))))));
# print the list and buuild the reverse list #
REF STRINGLIST node := list;
REF STRINGLIST reverse := REF STRINGLIST(NIL);
WHILE node ISNT REF STRINGLIST(NIL) DO
reverse := HEAP STRINGLIST
:= STRINGLIST( value OF node, reverse );
print((value OF node, space));
node := next OF node
OD;
print(newline);
# print the reverse list #
node := reverse;
WHILE node ISNT REF STRINGLIST(NIL) DO
print((value OF node, space));
node := next OF node
OD;
print(newline)
END
- Output:
Big fjords vex quick waltz nymph nymph waltz quick vex fjords Big