Question

What are constructors? Explain why they are needed in an object-oriented programming language. If inheritance takes place, what is the order in which the parent and child constructors are called? Can a constructor be overloaded? Can a constructor be overridden?

Explain when a destructor should be declared as virtual in C+?

Explain the use of the access specifiers public, protected and private in C++. Which is the default specifier?

Answer 1

Constructors are the blocks which are used to assign values to the variables.

Constructors call themselves unlike methods or functions means no need to call construtors .

If Inheritance takes place then first child constructors get the values from objects even child constructors hold the values of parent constructors also.

ParentConstructor(variableP)

{

}

ChildConstructor(VariableP,VariableC) : ParentConstructor(VariableP)

{

}

Yes, Constructor can be overloaded .One class can have multiple constructors.

No , a constructor can't be overridden.

when a destructor should be declared as virtual in C++, When there is at least one virtual function & an variable is  no more in used .

In Public access specifier, public data member  or data function or constructor are accessible globally and outside the class also.

In private access specifier, private data member  or data function or constructor are accessible within the class only.

In protected access specifier, public data member  or data function or constructor are accessible in child class only.

private is the default specifier in c++.

.