C++: Initialization of inherited field

Question

I\'ve a question about initialization of inherited members in constructor of derived class. Example code:

class A
    {
public:
    int m_int;
    };

class          


        

Answer 1

In order to construct an instance of class B you first instantiate an instance of class A. During that instantiation m_int gets initialized. It's after that intialization that b's constructor is called, so you can't reinitialize m_int. If that's your goal then you can implement a constructor for A that takes an int and then call that in B's initialization list:

class A
{
public:
  A(int x): m_int(x) {}
  int m_int;
};

class B: public A
{
public:
  B(): A(2) {}
};