Past paper (OOP)

Question 1

What is inheritance in OOP?

Answer 1

Subclasses inherit attributes & methods from parent classes, promoting code reuse and hierarchy.

Question 2

What is polymorphism in OOP?

Answer 2

Objects of different classes can be treated as instances of a common superclass or interface.

Question 3

How does polymorphism add flexibility?

Answer 3

Same method call behaves differently depending on object class implementation.

Question 4

Define encapsulation in OOP.

Answer 4

Bundling data (attributes) & methods inside a class, hiding internal object state from outside.

Question 4

Why is encapsulation important?

Answer 4

Protects data, prevents direct access, enhances security and maintainability.

Question 5

What is a mutator method?

Answer 5

Setter method that modifies object attributes; usually void and takes parameters.

Question 6

What is an accessor method?

Answer 6

Getter method that returns attribute value without changing it; no parameters.

Question 7

Compare mutator and accessor methods.

Answer 7

Mutator changes attribute; accessor returns attribute value without changing it.

Question 8

What is method overriding?

Answer 8

Subclass provides a new implementation for a method inherited from superclass with same signature.

Question 9

What is method overloading?

Answer 9

Multiple methods in the same class with same name but different parameter lists.

Question 10

Difference between method overriding and overloading?

Answer 10

Overriding: different classes, same method signature. Overloading: same class, same name, different parameters.

Question 11

What does a minus sign (-) mean in class diagram fields?

Answer 11

Private access modifier.

Question 12

What does a hash sign (#) mean in class diagram fields?

Answer 12

Protected access modifier (package or subclass access).

Question 13

How is a constant field represented in a class diagram?

Answer 13

All capital letters, underlined, with assigned value (e.g., MAXHOURS = 8).