What is the difference between template typename and template class?

What is the difference between template typename and template class?

There is no semantic difference between class and typename in a template-parameter. typename however is possible in another context when using templates – to hint at the compiler that you are referring to a dependent type. Without typename the compiler can’t tell in general whether you are referring to a type or not.

What is the difference between template typename T and template T?

There is no difference. typename and class are interchangeable in the declaration of a type template parameter.

Can template class be inherited?

Inheriting from a template class It is possible to inherit from a template class. All the usual rules for inheritance and polymorphism apply. If we want the new, derived class to be generic it should also be a template class; and pass its template parameter along to the base class.

Which keyword is used in template class typename?

When specifying a template template, the class keyword MUST be used as above — it is not interchangeable with typename in this case (note: since C++17 both keywords are allowed in this case).

What does template typename t do?

template This means exactly the same thing as the previous instance. The typename and class keywords can be used interchangeably to state that a template parameter is a type variable (as opposed to a non-type template parameter).

Is it possible to inherit from a template class in C++?

It is possible to inherit from a template class. If we want the new, derived class to be generic it should also be a template class; and pass its template parameter along to the base class.

How do you inherit a template class in C++?

1. inherit (template to template): template class Der : public Base
2. specialize Der. you must inherit it as template first then make the specilzation. template
3. inherit (class to template) template class Der : public Base
4. inherit (class to class) class Der : public Base

What’s the difference between typename and class in a template?

3 Answers 3. There is no difference. typename and class are interchangeable in the declaration of a type template parameter. You do, however, have to use class (and not typename) when declaring a template template parameter:

When to use the keyword typename instead of class?

It may seem more intuitive to use the keyword typename rather than class to designate a template type parameter. After all, we can use built-in (nonclass) types as a template type argument. Moreover, typename more clearly indicates that the name that follows is a type name.

Is there a semantic difference between class and typename?

There is no semantic difference between class and typename in a template-parameter. typename however is possible in another context when using templates – to hint at the compiler that you are referring to a dependent type. §14.6.2:

When to use typename in a dependent type?

The first one is in the case of dependent types. typename is used to declare when you are referencing a nested type that depends on another template parameter, such as the typedef in this example: The second one you actually show in your question, though you might not realize it: