How can I use a QMap::const_iterator as a pointer?

Question

How can I use a QMap<QString, QString>::const_iterator as a pointer?

QMap<QString, QString>::const_iterator *i = map -> constBegin();
        while (i  !=  map -> constEnd()) {
            qDebug() << i -> key() << ": " << i -> value();

            i++;
        }
}

I get the error:

/my_class.cpp:36: error: cannot convert ‘QMap<QString, QString>::const_iterator’ to ‘QMap<QString, QString>::const_iterator*’ in initialization
         QMap<QString, QString>::const_iterator *i = map -> constBegin();
                                                                                ^

You *don't?* An iterator might *emulate* a pointer by overloading the dereference operators but it is no pointer by itself. — Some programmer dude, Mar 25 '17 at 17:45
Thanks for the response @Someprogrammerdude. How else can I do it? I'm getting my `QMap` **`map`** as a pointer `*map`. — Program-Me-Rev, Mar 25 '17 at 17:58

zett42 · Answer 1 · 2017-03-25T18:10:42.737

The error is in this line:

QMap<QString, QString>::const_iterator *i = map -> constBegin();
                                       ~~

Here you are defining a pointer to a const_iterator but QMap::constBegin() returns just a const_iterator.

Simply remove the *, problem solved:

QMap<QString, QString>::const_iterator i = map -> constBegin();

The point is, an iterator already behaves similar to a pointer, so there is no need for the conventional syntax of defining a pointer.

Here is a great tutorial for iterators.

How can I use a QMap::const_iterator as a pointer?

1 Answers1