class CFoo
{
public:
int i;
CFoo() { int i=0;}
virtual ~CFoo() {};
};
class CBoo : public CFoo
{
public:
CBoo() {i = 1;} // Problem occurs here, it calls CFoo::CFoo, I don''t need that!
virtual ~CBoo() {}
};
One call to constructor when inheriting class..
Author
Hi guys,
I''ve been wondering how to call only ONE constructor when you derive a class from the other one?
For example, I got:
struct CFoo { CFoo(int x=0) : i(x) {} int i; }; struct BFoo : CFoo { BFoo() : CFoo(1) {} };
Author
No, I think you didn''t understood (or maybe I described it wrong)
I got a class and a member pointing to an interface:
So, what I need is that each class derived from IBlah (or other above it - e.g class CKoo : public CBoo ) will call ONLY its constructor, and won''t go thru others that it derived from.
Thanks.
" Do we need us? "
I got a class and a member pointing to an interface:
class IBlah{public:......etc};class CFoo{public:IBlah *m_pBlah;CFoo(){m_pBlah = new IBlah;etc};class IBleh : public IBlah{public:int fark;etc};class CBoo : public CFoo{public:......CBoo(){// Here comes the problem - I want m_pBlah to point to IBleh, not IBlahm_pBlah = new IBleh;}};So, what I need is that each class derived from IBlah (or other above it - e.g class CKoo : public CBoo ) will call ONLY its constructor, and won''t go thru others that it derived from.
Thanks.
" Do we need us? "
Perhaps you could write a ''dummy'' constructor in your base class, that will be called by each derived class constructor:
class CFoo{public: CFoo() { i = 0; };protected: int i; CFoo(short i, long j) { /*Do nothing*/ };};class CBoo : public CFoo{public: // This default CBoo constructor calls the dummy CFoo // constructor that does *nothing* CBoo(): CFoo(0, 0) { i = 1; };};
The base class constructor must be called. Magmai showed you the way to do it properly - initialize the base class member through a constructor argument:
class CFoo{public:IBlah *m_pBlah;CFoo(IBlah* bptr) : m_pBlah(bptr) { }};class CBoo : public CFoo{public:CBoo() : CFoo(new IBleh) { }};
Do you have some sample code from your program? Perhaps inheritance is the wrong solution for your problem anyway.
--
Dave Mikesell
d.mikesell@computer.org
http://davemikesell.com
--
Dave Mikesell
d.mikesell@computer.org
http://davemikesell.com
Author
Thanks all, spoke has a correct solution I think.
Thanks again.
" Do we need us? "
Thanks again.
" Do we need us? "
This topic is closed to new replies.
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