Function returning a linked list

[dhanny]

Hi, mates.
I wrote the function and it runs properly, but i don't know how to make it return a List object correctly.
It should be like:
List list = Function(arguments);
but when i type it thatway it crushes.
Should my function be of a List& type ?
Thank you in advance!

[helios]

Usually, when you want to pass around objects more than a few bytes long, you pass a pointer to them, instead.

[dhanny]

So you mean i should have List* Function(arguments)
and then List* list = Function(arguments) ?
how to use list then ?

[helios]

What do you mean "how to use it"? You use it like you would any other pointer.

[dhanny]

I mean when "list" is a pointer, how can i use list's methods i defined i its class ?
like print() for example ?

[firedraco]

You use it like you would any other pointer.

I.e.:

List list;
List* pointer = &list;
pointer->stuff();

[dhanny]

I guess I'm too stupid but it doesn't work for me...
My code is like that :

List Function (arguments)
{
    ...
   return list;
}

List* list = &Function(arguments);
list->print()

Everything else works fine... even if i move the body of the function to the main() it works as i want it to work... but that problem with returning a list I cant fix :(

[firedraco]

You can't do: List* list = &Function(arguments);

IIRC, this tries to find the data address of the function...make the function return a List* then just set the List* you are creating to the result of the function.

[dhanny]

But if i try :

List Function (arguments)
{
    ...
   List* asdf = &list
   return asdf;
}

List* list = Function(arguments);
list->print()
}

it crushes again :(

[helios]

Why does the signature say the function returns a List instead of a List *?

You're trying to return a pointer to a local object. Local objects are destructed when the function that created them returns, so that means you're returning an invalid pointer.
Read this on dynamic memory allocation:
http://www.cplusplus.com/doc/tutorial/dynamic.html

[roodtree]

so we can :
return list;???

[grey127]

you can return a pointer and from that Pointer you can move further ....

like

if you return ptr ; <ptr is a Pointer >

than you can go like this ptr->next->next ..... and so on to yur desired place ..

[Dacster13]

You just need to return the head node of the list, since the list is made up of pointers, the head node would be pointing to the next node.

[dhanny]

Ok, but how can i use a pointer to a list, which is destructed then ? :(
Then i should return the list itself ??
i wanted it to be something like that :

List* Function (List& list1, List& list2)
{
   List list = list1;
    ...
   List* asdf = &list
   return asdf;
}

List* list = Function(arguments);
list->print()
}

I understood that after returning the pointer asdf, list is destructed... Can i saomehow preserve destructing it while executing the whole program or is there any other appropriate solution ?

[helios]

I didn't post this link to show the pretty colors:
http://www.cplusplus.com/doc/tutorial/dynamic.html

[dhanny]

sorry and thank you, helios!