C++ 基类访问规范与类成员访问规范

基类访问规范与成员访问规范有何不同？

基类访问规范决定了类中基类成员的访问规范。如果您不希望基类成员在类中公开出现，它们提供了一种隐藏基类成员的方法。但是，它们不会影响类成员的可见性

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
};