C++ |重用基类的 protected 成员

Question

假设我有一个基类和派生类:

class Base{
 private:
  int* _privateIntPtrB;
 protected:
  int* _protectedIntPtrB;
 public:
  //methods which use
  //_privateIntPtrB and _protectedIntPtrB

class Derived: public Base{
 private:
  int* _privateIntPtrD;
 protected:
  int* _protectedIntPtrB; //I am redeclaring this var
 public:
  //methods which use
  //_privateIntPtrD and _protectedIntPtrB

我的问题:在 Derived 类的方法中，是否使用了 _protectedIntPtrB 的派生版本？ (我认为是的，但想确认)。

如果 Derived 类未重新定义方法，则指向 Derived 类的指针将使用哪个版本的 _protectedIntPtrB？

我问的原因 - 我想以不同方式初始化 Derived 类中的 _protectedIntPtrB 并希望使用该版本的 _protectedIntPtrB在派生类的所有实例中。

Answer 1

In the methods of the Derived class, does the Derived version of _protectedIntPtrB get used?

是的，它隐藏了基类成员，因此在 Derived 范围内对 _protectedIntPtrB 的非限定使用指的是 Derived::_protectedIntPtrB . (如果限定为 Base::_protectedIntPtrB，基类变量仍然可用)。

If a method is not redefined by the Derived class, which version of the _protectedIntPtrB will be used by a pointer to Derived class?

基类变量。派生类的数据成员不可从基类获得。

The reason I am asking - I want to initialize _protectedIntPtrB in the Derived class differently and want that version of the _protectedIntPtrB to be used in all the instances of Derived class.

通常，使派生类的行为与其基类不同的最佳方法是覆盖虚函数。如果您能准确地考虑您想要实现的目标，可能会更好:找出您想要修改的行为，并将其封装在虚函数中。