Use std container iterator in template class

Question

I can't use the std container iterator in a template class.

I get this errors :
error C2061: syntax error : identifier 'iterator'
error C2238: unexpected token(s) preceding ';'

Here the source code:

#include <list>
#include <functional>
#include <memory>

template<typename TParam>
class MyClass
{
public:
    using TFunction = std::function<void(TParam)>;
    using TContainer = std::list<TFunction>;
    using TIterator = TContainer::iterator; // compilation error here!
};

How to use the iterator of the container in the templated class?

The compiler error is common, and what I wanted to do is specific, so I didn't find the same question.. — Antoine, Jan 08 '16 at 11:43

score 1 · Answer 1 · edited May 23 '17 at 11:51

1

You need the typename keyword

using TIterator = typename TContainer::iterator;

Depending on what TContainer ends up being, the iterator could be a static member or a nested type. The compiler will assume it's not a type unless you explicitly specify that with the typename keyword. See here for more details.

edited May 23 '17 at 11:51

Community

1
1

answered Jan 08 '16 at 11:39

Armen Tsirunyan

130,161
59
324
434

Great it works ! Why this keyword here? – Antoine Jan 08 '16 at 11:39
@AntoineLafarge: See my edit – Armen Tsirunyan Jan 08 '16 at 11:40

Use std container iterator in template class

1 Answers1