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What is a dependent name?

What is a dependent name?

A dependent name is a name that depends on the type or the value of a template parameter. For example: template class U : A { typename T::B x; void f(A& y) { *y++; } }; The dependent names in this example are the base class A , the type name T::B , and the variable y .

Does C++ have dependent types?

Technically (and truly), C++ has dependent types, as types can depend on values [edit: matt-noonan has corrected me and pointed out this is wrong, but I think most of this comment is still useful].

What is a type name in C++?

” typename ” is a keyword in the C++ programming language used when writing templates. It is used for specifying that a dependent name in a template definition or declaration is a type.

Where and why do I have to put the template and typename keywords?

The typename keyword before a dependant name specifies that it is the name of a type. Use the keyword typename only in template declarations and definitions provided you have a qualified name that refers to a type and depends on a template parameter.

Which is Dependant on template parameter?

Which is dependant on template parameter? Explanation: Base class is dependant on template parameter.

How many types of templates are there in C++?

There are three kinds of templates: function templates, class templates and, since C++14, variable templates. Since C++11, templates may be either variadic or non-variadic; in earlier versions of C++ they are always non-variadic.

What are dependent functions?

A dependent function type describes function types, where the result type may depend on the function’s parameter values. The concept of dependent types, and of dependent function types is more advanced and you would typically only come across it when designing your own libraries or using advanced libraries.

Are dependent types useful?

Dependent types are incredibly useful for ‘real programming’, and a natural extension of type systems we use on a regular basis, and I seek to explain why.

What is type Def in C?

typedef is a reserved keyword in the programming languages C and C++. It is used to create an additional name (alias) for another data type, but does not create a new type, except in the obscure case of a qualified typedef of an array type where the typedef qualifiers are transferred to the array element type.

What is using keyword in C++?

​The using keyword is used to: Bring a specific member from the namespace into the current scope. Bring all members from the namespace into​ the current scope. Bring a base class method ​or variable into the current class’s scope.

Which is dependent on template parameter?

Why do I need typename?

typename is needed in your declaration of ‘it’ because otherwise the compiler doesn’t know that it’s a type declaration rather than an expression. According to this page, “Use the keyword typename if you have a qualified name that refers to a type and depends on a template parameter.”