Class declaration
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目次 |
[編集]構文
classidentifier{class_body} object_list; | (1) | ||||||||
classidentifier:ancestor_list{class_body} object_list; | (2) | ||||||||
classidentifier; | (3) | ||||||||
| classidentifierfinalopt_ancestors_and_body | (4) | (C++11およびそれ以降) | |||||||
[編集]Class Body
A list of member and friend declarations and access specifiers:
| public: | (1) | ||||||||
| protected: | (2) | ||||||||
| private: | (3) | ||||||||
| friendfriend_declaration | (4) | ||||||||
| member_declaration | (5) | ||||||||
| staticmember_declaration | (6) | ||||||||
| nested_type_declaration | (7) | ||||||||
[編集]Ancestor List
A list of classes that have already bee fully defined optionally prefixed with an access specifier
[編集]Object List
An optional list of instances of the previously defined class
[編集]説明
- Defines a class and its member
- Defines a class inheriting other classes
- Forwards declares a class
- Defines a class that cannot be derived from ( see final )
If friend or member functions have their body defined inside the class body, they are implicitly inlined
[編集]ノート
(C++11およびそれ以降) A default value can be assigned to data members inside the class body (ie: not necessarily in a constructor)
[編集]参照
[編集]例
class C; class D :public B // B needs to be defined{private: C *ptr_c;// a pointer/reference to C can be used as C has been forward declareddouble x =12.3;// C++11 inline data member initializationstaticconstint sci =1;// this is valid in C++98 as wellpublic:typedef B parent_type; // inline functionvirtual parent_type foo()const{return B();} // non-inline function declaration. needs to be defined externallyvoid bar();} D_obj;// An object of type D is defined // definition of a class method outside the classvoid D::bar(){//...}
