c++ - 基类访问规范与类成员访问规范

Question

基类访问规范与成员访问规范有何不同？

Answer 1

基类访问规范决定了您的类中基类的成员访问规范。如果您不希望基类成员公开出现在您的类中，它们提供了一种隐藏基类成员的方法。但是，它们不会影响您班级成员的可见性。

C++ FAQ很好地解释了这个问题。

class Base
{
protected:
    int A;
public:
    int B;
};

class Derived1 : public Base
{
    // Derived1::A outside class is seen as protected
    // Derived1::B outside class is seen as public
};

class Derived2 : protected Base
{ 
    // Derived1::A outside class is seen as protected
    // Derived1::B outside class is seen as protected
};

class Derived3 : private Base
{ 
    // Derived1::A outside class is seen as private
    // Derived1::B outside class is seen as private
};