CODEWITHSUNDEEP
c++c++11iterator
Antonio1996
Antonio1996

Reputation: 756

How to use iterator as parameters method?

I have this situation: 

 void methodB(list<int>::iterator myIt){
    myIt++;
}
void methodA(){
    list<int> * myList=new list<int>();
    list<int>::iterator it=myList->begin();
    //many insertion in myList ...
    methodB(it);
    //...
}

I want that, when methodB ends, the iterator is one position forward but I can't do this... if I'm in methodA() and many times call methodB(it), every time the iterator is copied and when the control return to methodA() the it variable is always in myList->begin(). How can I solve this problem? Thanks

Upvotes: 2

Views: 64

Answers (2)

Richard Hodges
Richard Hodges

Reputation: 69882

A good model for this is std::next, which returns a modified copy of the iterator:

list<int>::iterator
methodB(list<int>::iterator myIt){
    myIt++;
    return myIt;
}

void methodA(){
    list<int> * myList=new list<int>();
    list<int>::iterator it=myList->begin();
    //many insertion in myList ...
    it = methodB(it);
    //...
}

https://en.cppreference.com/w/cpp/iterator/next

Note that container iterators are designed to be cheap to copy.

Upvotes: 2

Edgar Rokjān
Edgar Rokjān

Reputation: 17483

You need to pass it by reference, like:

void methodB(list<int>::iterator& myIt);

Upvotes: 2

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