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What is encapsulation??
Containing and hiding information about an object, such as
internal data structures and code. Encapsulation isolates the
internal complexity of an object's operation from the rest of
the application. For example, a client component asking for net
revenue from a business object need not know the data's origin.
What is inheritance?
Inheritance allows one class to reuse the state and behavior
of another class. The derived class inherits the properties and
method implementations of the base class and extends it by
overriding methods and adding additional properties and methods.
What is Polymorphism??
Polymorphism allows a client to treat different objects in
the same way even if they were created from different classes
and exhibit different behaviors. You can use implementation
inheritance to achieve polymorphism in languages such as C++ and
Java. Base class object's pointer can invoke methods in derived
class objects. You can also achieve polymorphism in C++ by
function overloading and operator overloading.
What is constructor or ctor?
Constructor creates an object and initializes it. It also
creates vtable for virtual functions. It is different from other
methods in a class.
What is destructor?
Destructor usually deletes any extra resources allocated by
the object.
What is default constructor?
Constructor with no arguments or all the arguments has
default values.
What is copy constructor?
Constructor which initializes the it's object member
variables ( by shallow copying) with another object of the same
class. If you don't implement one in your class then compiler
implements one for you.
for example:
Boo Obj1(10); // calling Boo constructor
Boo Obj2(Obj1); // calling boo copy constructor
Boo Obj2 = Obj1;// calling boo copy constructor
When are copy constructors called?
Copy constructors are called in following cases:
a) when a function returns an object of that class by value
b) when the object of that class is passed by value as an
argument to a function
c) when you construct an object based on another object of the
same class
d) When compiler generates a temporary object
What is assignment operator?
Default assignment operator handles assigning one object to
another of the same class. Member to member copy (shallow copy)
What are all the implicit member functions of the class? Or
what are all the functions which compiler implements for us if
we don't define one.??
default ctor
copy ctor
assignment operator
default destructor
address operator
What is conversion constructor?
constructor with a single argument makes that constructor as
conversion ctor and it can be used for type conversion.
for example:
class Boo
{
public:
Boo( int i );
};
Boo BooObject = 10 ; // assigning int 10 Boo object
What is conversion operator??
class can have a public method for specific data type
conversions.
for example:
class Boo
{
double value;
public:
Boo(int i )
operator double()
{
return value;
}
};
Boo BooObject;
double i = BooObject; // assigning object to variable i of type
double. now conversion operator gets called to assign the value. |
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