ISRO-DEC2017-65

Question

Which one of the following are essential features of object-oriented language?
 

A.	Abstraction and encapsulation
B.	Strictly-typed
C.	Type-safe property coupled with sub-type rule
D.	Polymorphism in the presence of  inheritance

• A.  $A$ and $B$ only 
• B.  $A,D$ and $B$ only 
• C.  $A$ and $D$ only 
• D.  $A,C$ and $D$ only

Comments

https://gateoverflow.in/1346/gate2005-4

Answer 1

Essential features of object-oriented language are 

1. Inheritance: forming a new class from an existing class. It helps to reuse code.  
2. Abstraction: Provide only essential information to the outside world and hide background details.  
3. Overloading: specify more than one definition for a function name or an operator in the same scope.
4. Polymorphism: A call to a member function will invoke a different function depending on the type of object that invokes the function.
5. Encapsulation: Binding data and functions accessing the data together and that keeps both safe from outside interference and misuse.

Now, go through the given options,

• A is true.
• B is false ( Perl is a loosely typed language but supports OOPS),
• C is false
• D is true

Answer is C)  A and D only