Override or remove an inherited constructor

Question

Here is some C++ code:

#include <iostream>
using namespace std;

class m
{
    public:
    m() { cout << "mother" << endl; }
};

class n : m
{
    public:
    n() { cout << "daughter" << endl; }
};

int main()
{
    m M;
    n N;
}

Here is the output:

mother  
mother  
daughter

My problem is that I don't want the m's constructor to be called when I create N. What should I do ?

Answer 1

AFAIK, you cannot remove inherited constructor.

The problem in your example comes from incorrect class design. Constructor is normally used for allocating class resources, setting default values, and so on. It is not exactly suitable to be used for outputting something.

You should put

n() { cout << "daughter" << endl; }

Into virtual function.

In general - if you have a need to remove inherited constructor, then you probably need to rethink/redesign your class hierarchy.

Answer 2

class m
{
public:
      m(bool init = true) { if (init) cout << "mother" << endl; }
};


class n : m
{
public:
      n() : m(false) { cout << "daughter" << endl; }
};

or if you don't want it to be public

class m
{
protected:
    m(bool init) { if(init) Init(); }
    Init() { cout << "mother" << endl; }

public:
      m() { Init(); }
};

class n : m
{
public:
      n() : m(false) { cout << "daughter" << endl; }
};