Question

Is there a difference between a class template and template class. If so what is it?

Answer 1

When both terms are used there is a very subtle difference. It is more linguistic than semantic, it depends on which word you are modifying.

In short, a class template is a particular kind of template. Templates can define either classes or functions. A class template is a template that defines a class. See the difference:

template <typename T> class SomeClass {...};      // this is a class template
template <typename T> int some_function(T&) {...} // this is a function template

A template class is a particular kind of class. There are many kinds of classes, and in particular, template classes are those defined using a class template. Contrast:

SomeClass sc;         // SomeClass is an ordinary (non-template) class
SomeClass<int> sc;    // SomeClass<int> is a template class

From Stroustrup’s C++ Glossary:

template class – class parameterized by types, values, or templates. The
template arguments necessary to identify the class to be generated for
the class template must be provided where a template class is used. For
example “vector<int> v;” generates a vector of ints from the vector
template. See also template. TC++PL 13.2, D&E 15.3.

Both expressions are used in Stroustrup’s book The C++ Programming Language, and the ISO/IEC C++ standard until 1998.

Note: As discussed in the comments below, it seems that C++03 doesn’t use the term “template class” anymore (although I don’t have a copy of it), presumably to reduce confusion. As I said before, they are fundamentally the same thing, it is just a linguistic difference: in the templates context you refer to a particular kind of template or in the classes context you refer to a particular kind of class. If you just stick to “class template”, you won’t lose anything.

More food for thought:

• What is the difference between a template class and a class template?
• Is there a difference between a function template and a template function, or between a class template and a template class? — link suggested by Josh Haberman