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Difference between revisions of "cpp/keyword/typename"

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{{cpp/keyword/title|typename}}
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{{cpp/keyword/title|{{tt|typename}}}}
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===Usage===
 
===Usage===
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*In a [[cpp/language/template | template declaration]] used to declare templated types
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* In the template parameter list of a [[cpp/language/templates|template declaration]], {{c|typename}} can be used as an alternative to {{lt|cpp/keyword/class}} to declare {{lsd|cpp/language/template parameters#Type template parameter}}s{{rev inl|since=c++17| and template template parameters}}.
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*Inside a template definition, to declare that a static member of a class depending on a template is a type
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* Inside a declaration or a definition of a template, {{c|typename}} can be used to declare that a [[cpp/language/dependent name|dependent qualified name]] is a type.
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===Example===
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* {{c|typename}} can be used before a non-dependent qualified type name. It has no effect in this case.
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{{example|code=
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{{rrev|since=c++20|
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template <typename T>
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* Inside a [[cpp/language/constraints|requirements]] for type requirements
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    void foo ( const std::vector<T>& v )
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    {
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        typename std::vector<T>::const_iterator it = v.begin();
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    }
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}}
 
}}
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===See also===
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* {{rlpt|class}}
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* {{rlpt|template}}
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{{rrev|since=c++20|
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* {{rlpt|concept}}, {{rlpt|requires}}
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}}
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{{langlinks|de|es|fr|it|ja|pt|ru|zh}}

Latest revision as of 04:44, 14 August 2024

 
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[edit] Usage

  • In the template parameter list of a template declaration, typename can be used as an alternative to class to declare type template parameters and template template parameters(since C++17).
  • Inside a declaration or a definition of a template, typename can be used to declare that a dependent qualified name is a type.
  • typename can be used before a non-dependent qualified type name. It has no effect in this case.
(since C++20)

[edit] See also

(since C++20)
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