Re: Strings with Templates not working?

From:

"Victor Bazarov" <v.Abazarov@comAcast.net>

Newsgroups:

comp.lang.c++

Date:

Wed, 20 Jun 2007 16:36:53 -0400

Message-ID:

<f5c357$eq9$1@news.datemas.de>

Markus Pitha wrote:

Victor Bazarov schrieb:

Markus Pitha wrote:

[..]
template <class T>
T ListT<T>::get(int i) {
TKnoten *iterator = new TKnoten();

HUH? Why are you creating another 'TKnoten' here?

How can I iterate over the whole list then without an extra object?

That's a strange question. When you need to look for something in
your desk drawers, do you go out an buy another drawer? When you
need to look for something in some text files on your hard drive,
do you first create another file? No, you just open them, look in
them, and move on.

To iterate over objects that exist in your list, all you need is
a pointer where you will store the address of the existing objects.
There is no need to create another object to immediately lose its
address because you assign 'kopf' to 'iterator' two lines down.

T daten = 0;
iterator = kopf;

Again, you're immediately losing the value of 'iterator' that you
just obtained from 'new'...

    while (iterator->next != 0) {
         if (iterator->index == i) {
            daten = iterator->daten;
         }
         iterator = iterator->next;
    }
    delete iterator;

Are you sure you need to 'delete' it here?

I thought that I have to delete everything I allocated with "new"?

Yes, but *what* are you deleting? It would seem to me that you
are actually deleting the last element of the list...

You should undoubtedly attempt to write your own linked list at some
point in your studies. But you need to pay attention to what you're
doing.

V
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