What is the difference between “template ” and “template ”? [duplicate]

Answer 1

If by

template <typedef T> class SampleClass2

you mean

template <typename T> class SampleClass2

then there is no difference. The use of class and typename (in the context of a template parameter that refers to a type) is interchangeable.

The reason that both keywords are allowed here is historical. See this article for a detailed explanation.

Answer 2

In case of template template paramater

template <typename T, template <typename> class Wrapper>
class Foo {
    //...
  private:
    Wrapper<T> data;
};

You have to use class before classname. This is wrong:

template <typename T, template <typename> typename Wrapper>

but this is ok:

template <typename T, template <class> class Wrapper>

In other cases they are interchangeable.