该继承的类将调用哪个方法（虚拟函数）？ C ++

Question

Say I have a base class

class Base
{

public:
void A() {do stuff};
void B() {A(); do stuff};
};

and a derived class

class Derived : public Base
{
public:
void A() {do things}
};

Derived derived1;
derived1.B();

will B call A of the base class or the A of the derived class?

I suspect B will call the A of the base class, and that in order for it to use the new redefined A, I have to make it virtual:

class Base
{

public:
virtual void A() {do stuff};
void B() {A(); do stuff};
};

Is that correct? Is that what virtual functions are used for?

Answer 1

是的，在两个方面都正确...

Answer 2

try this

class Base
{
public:
virtual void A() {do stuff};
void B() { do stuff};
};

class Derived : public Base
{
public:
void A() {do things}
void B() {do things}
};

and

Derived d;
Base *p = &d;
p->A();
p->B();

function B will not be overrided