Constructor of Nested Classes of Templates Classes in C++

Question

I have a nested class inside a template class and wish to implement its constructor outside of the scope. However, I get the following error:

expected unqualified-id before ')' token

template<class T>
class mainClass {
private:
    class nestedClass {
    public:
        nestedClass();
    };
};

template<class T>
typename mainClass<T>::nestedClass::nestedClass(){
    // code here
}

score 0 · Answer 1 · edited May 23 '17 at 12:22

0

Remove the typename:

template<class T>
mainClass<T>::nestedClass::nestedClass(){
    // code here
}

Live Demo

For more info on in which contexts we need to use typename see here.

edited May 23 '17 at 12:22

Community

1
1

answered Jun 07 '16 at 20:14

101010

41,839
11
94
168

It doesn't work. I think it must have a typename for the compiler to realize that nestedClass is a type and not something else (e.g. a static variable or a function). – Guy Waldman Jun 07 '16 at 20:17

score 0 · Answer 2 · answered Jun 07 '16 at 20:55

0

It seems my problem concerned another bug which I had not noticed up until now. In any regard, it is true that typename was not required in the context in which it was used.

Thank you.

answered Jun 07 '16 at 20:55

Guy Waldman

457
3
12

Constructor of Nested Classes of Templates Classes in C++

2 Answers2