没有匹配的函数来调用…类模板错误

Question

i have to do a generic double linked list, and i made it in vc++ 2010, and everything worked well, but i have to compile it with gcc, but it can't compile it. When i call a method which has an iterator as parameter, i got this error:

no matching function for call to 'DLList<int>::Erase(DLList<int>::iterator, DLList<int>::iterator)'| 
[...]note: candidates are: void DLList<T>::Erase(DLList<T>::iterator&, DLList<T>::iterator&) [with T = int]|

The DLList is in a .h file, and every method defined inline. The iterator class is also in the DLList class.

template<typename T>
class DLList{
[...]
public: 
[...]
    void Erase(iterator &_first, iterator &_last){...}
    iterator first(){...}
    iterator last(){...}
[...]
    class iterator{...}
[...]
};

And the code which causes the error:

iList.Erase(iList.first(), iList.last());

(iList: DLList< int> iList)

How can i fix it?

Answer 1

void Erase(iterator const &_first, iterator const &_last){...}

This allows your temporary iterators, returned from first() and last() , to be passed. You cannot get a non-const reference to a temporary.

Alternatively, you could use this function signature and work on iterator copies (if you eg need to modify them within Erase ):

void Erase(iterator _first, iterator _last){...}

Answer 2

The problem is that a non-const reference cannot be bound to a temporary. The result of first() and last() are temporaries, and those cannot be bound by the references in the signature of Erase .