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what is virtual destructor
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Answer / isha
Dear friend , you have done a mistake..
Example:
class Employee {
virtual ~Employee() {}
};
class Manager : public Employee {
~Manager() {}
}
Employee * m = new Manager();//here was the mistake
delete m; // <--
| Is This Answer Correct ? | 9 Yes | 0 No |
Answer / kamil mohamed
virtual destructor is recommended when you want to destroy
(delete) an object through it's parent pointer. This good
habit enforces proper cleanup of derived classes
Example:
class Employee {
virtual ~Employee() {}
};
class Manager : public Employee {
~Manager() {}
}
Manager * m = new Employee();
delete m; // <--
| Is This Answer Correct ? | 6 Yes | 1 No |
Answer / rock
When a derived class object pointed to by a base class
pointer dynamically is deleted only the base class
destructor is invoked inorder to even invoke derived class
destructor we use virtual destructor.
class shape
{
virtual ~shape(){}
};
class circle:public shape
{
~circle(){}
};
void main()
{
shape *sh = new circle;
delete sh; //both the destructors are invoked
}
If virtual keyword is not added to the base class
destructor only the base class destructor is called.
| Is This Answer Correct ? | 3 Yes | 0 No |
Answer / pankajkolte
Virtual Destructor is used basically to ensure proper the
sequence of call to destructor.
class Employee {
virtual ~Employee() {}
};
class Manager : public Employee {
~Manager() {}
}
Employee * m = new Manager();//here was the mistake
delete m; // <-
In this case base class destructor if marked as virtual so
as derived class destructor will get called first then base
class destructor.
| Is This Answer Correct ? | 2 Yes | 0 No |
Answer / suresh.k (portblair)
Using virtual destructors, you can destroy objects without
knowing their type - the correct destructor for the object
is invoked using the virtual function mechanism. Note that
destructors can also be declared as pure virtual functions
for abstract classes.
if someone will derive from your class, and if someone will
say "new Derived", where "Derived" is derived from your
class, and if someone will say delete p, where the actual
object's type is "Derived" but the pointer p's type is your
class.
| Is This Answer Correct ? | 2 Yes | 4 No |
Answer / rahul
virtual destructor is just to remove the variable without
knowing its type.....
| Is This Answer Correct ? | 0 Yes | 3 No |
Normally virtual destructor is used to destroy a base class
object without knowing it's type...
| Is This Answer Correct ? | 0 Yes | 3 No |
Which method cannot be overridden?
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Can we create object of abstract class?
how does a main() in C++ is different from main() in C?
difference between abstraction and encapsulation with progarammatic eg. hi,just recently i went for an interview .The interviewer asked what is the difference between abstraction and encapsulation with programmatic eg. I gave the answer as encapsulation mean hiding the relevant data which is not useful for the user, eg a electric fan .hiding the information how the electricity is converted into machanical energy. abtraction showing only the relevant data to the user eg electric fan. it look ,its color ,it design etc only relevant data. Then the interviewer asked me, give me some programmic eg .I Said Let assume a web form having control like textbox,button etc. The user can view textbox,button etc this is the eg of abstraction and when the user click on the button how he is redirected is not known by the user is the eg of the encapsulation. Am I Correct .was the answer given by me is perfect .now i am planing to go for an another interview should i give the same answer.IF not please suggest me a better answer.with some good eg Please help
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Write a program to implement OOPS concepts such as inheritance, polymorphism, friend function, operator overloading?
They started with the brief introduction followed by few basic C++ questions on polumorphism, inheritance and then virtual functions. What is polymorphims? How you will access polymorphic functions in C? How virtual function mechanism works?
What is the use of oops?
1.explicit call for destructor 2.calling function inside a constructor. 3.base *b-new derived delete b; 4.delete p what it will delete. 5.size of base class and derived class int i,in base class and int j in derived. 6.int i-20 int main() { int i =5; printf("%d".::i); { int i =10; printf("%d".::i); } } 7.object slicing 8.new 9.function overloading(return type). 10.class base() { virtuval fun() { ----- } } class derivied:public base() { fun() { ----- } } int main() { derived d; } 11.how static function will call in C++? 12.default structures are in C++? 13.constructors should be in public . 14.virtuval constructor not exist. 15.multilevel inhritence. destructor order.
State what is encapsulation and friend function?
STL 
