C.52: Use inheriting constructors to import constructors into a derived class that does not need further explicit initialization
C.52:使用繼承的構造函數功能將構造函數導入不再需要進一步明確初始化的派生類
Reason(原因)
If you need those constructors for a derived class, re-implementing them is tedious and error-prone.
如果派生類需要那些構造函數,重新實現它們的工作單調乏味而且容易發生錯誤。
Example(示例)
std::vector has a lot of tricky constructors, so if I want my own vector, I don't want to reimplement them:
std::vector有大量的構造函數很難用,因此如果我需要自己的vector,我不會重新實現它們。
class Rec {
// ... data and lots of nice constructors ...
};
class Oper : public Rec {
using Rec::Rec;
// ... no data members ...
// ... lots of nice utility functions ...
};
Example, bad(反面示例)
struct Rec2 : public Rec {
int x;
using Rec::Rec;
};
Rec2 r {"foo", 7};
int val = r.x; // uninitialized
這就是需要進一步初始化的例子。如果派生類沒有增加數據成員只是增加一些功能,就可以使用using Rec::Rec這種方法導入基類的構造函數。對於上面的例子也可以考慮使用類內初始化器初始化數據成員x。
Enforcement
Make sure that every member of the derived class is initialized.
保證派生類的所有成員都被初始化。
原文鏈接
https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md#c52-use-inheriting-constructors-to-import-constructors-into-a-derived-class-that-does-not-need-further-explicit-initialization
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