Chapter 2, Class and Function Templates

1. A template is not a type; it is a Factory for many different types with similar structures. A template is written in terms of generic types; substituting concrete types for these generic types results in a type generated from the template.
2. There are class, function, and variable templates. Each kind of template generates the corresponding entities—functions in the case of function templates, classes (types) from class templates, and variables from variable templates.
3. Templates can have type and non-type parameters. Type parameters are types. Non-type parameters can be integral or enumerated values or templates (in the case of variadic templates, the placeholders are also non-type parameters).
4. A template instantiation is the code generated by a template. Usually, the instantiations are implicit; the use of a template forces its instantiation. An explicit instantiation, without use, is also possible; it generates a type...