COPY CONSTRUCTORS and VIRTUAL DESTRUCTORS

[Subramaniam s V]

can anyone help me out in clearly understanding the concept of COPY CONSTRUCTORS and VIRTUAL DESTRUCTORS. I have gone through lots of books but still i am not much clear as why we go for COPY CONSTRUCTORS and VIRTUAL DESTRUCTORS. Kindly help me out.

[Nyarlatotep]

Virtual destructors have the same meaning of virtual methods. Those are useful if you use a base class pointer to hold a derived class pointer. if base class destructor is not virtual : class A { public: ~A() { cout << "Class A destructor"; } }; class B : public A { public: ~B() { cout << "Class B destructor"; } }; B *Bobj = new B; A *Aobj = Bobj; delete Aobj; Only the A destructor is invoked. if you make A destructor Virtual, the destructors of derived class and base class (in this order) are invoked. Copy constructors are used to copy an object, in these cases: MyClass obj; MyClass obj2(obj); // Copy constructor invoked MyClass obj = obj2; // Copy construcotr invoked obj = obj2, in this case the assignment operator is used ...

[toxcct]

copy constructor have an explicit enough name ! it gets another instance of its class, and duplicate it into "this"... imagine in one class, you have a pointer to an object. if you make a simple copy, you would duplicate actually the address, ,not the object pointed. a copy constructor allow you to make a deep copy... virtual destructors is another topic, with no relation with the first one. in a general mean, you tell a destructor to be virtual if you think that you class can be derived.

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[_AnsHUMAN_]

Subramaniam s.V. wrote:

COPY CONSTRUCTORS

A copy constructor is used to copy the contents of one object to another. A copy constructor unlike the assignment operator is also responsible for creating the object alongwith the initialization. Ex: class sample { public: sample() { } sample(sample &s) { cout<<"In Copy Constructor:"<

Subramaniam s.V. wrote:

VIRTUAL DESTRUCTORS. We need virtual destructors to perform memory cleanup from derived class to the base class.

Somethings seem HARD to do, until we know how to do them. ;-)_AnShUmAn_

[Hamid Taebi]

See here[^] and here[^] maybe it is some helpful to you

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WhiteSky

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