Another inheritance question

[Mor1994]

Hi everyone!
can you please explain me WHY in the C class,the line "B _b1;"
doesnt activate the B deafault CTOR?

and i will be glad to get some advices on those codes, i can not answer them correctly, a lot of mistakes..
when do the derived CTOR is called? and so on.. THANKS !

 class A 
{
public:
	A()			{cout<<"(1)"<<endl;}
	A(A& a)		{cout<<"(2)"<<endl;}
	virtual void f()  {cout<<"(3)"<<endl;}	
	virtual A g() {h(); cout<<"(4)"<<endl; return *this;}
	virtual A& h(){A::f(); cout<<"(5)"<<endl; return *this;}
	~A()	   {cout<<"(6)"<<endl;}
};

class B : public A
{
	int _x;
	A _a1;
	A* _ptr;
   public:
	B():_x(0),_ptr(0)	{cout<<"(7)"<<endl;}
	B(int num):_x(num),_ptr(0)	{cout<<"(8)"<<endl;}
	virtual void f()	      {g();cout<<"(10)"<<endl;}
	A g()		      {cout<<"(11)"<<endl; return A::g();}
 	B k()		           {cout<<"(12)"<<endl; return *this;}
    ~B()	  		      {cout<<"(13)"<<endl;}
};


class C : public B, public A
{
	B _b1;
   public:
	C():_b1(0)	{cout<<"(14)"<<endl;}
	A g()		{cout<<"(15)"<<endl; B::k(); return *this;}
	virtual void k()	{cout<<"(16)"<<endl;}
	virtual ~C()	{cout<<"(17)"<<endl;}
};

[AbstractionAnon]

line 31: _b1 is constructed using B's constructor that accepts an int (line 19).

[Mor1994]

but why not with the default CTOR? in the private section (line 29) it already declared..

[AbstractionAnon]

Because you used the initialization syntax

:_b1(0) 

That overrides any use of the default constructor. You stated you wanted the int constructor. You can't instantiate an object (_b1) with two different constructors (default and int).