ITPEC FE Subject A October 2024 Question 35

In object-oriented programming, which of the following is abstraction?

a)Concealing implementation details and exposing only a simplified interface for interacting with objectsb)Creating a subclass instance inheriting attributes and behaviors from its superclassc)Defining multiple methods with the same name but different parametersd)Redefining in the child class a method that is already provided by the superclass with the same name and parameters but a different implementation

Explanation

Hiding implementation details behind a simplified interface — abstraction lets users work with what an object does, not how it does it.

Abstraction picks out an object's essential characteristics and exposes them through a simple interface (in code, an abstract class or interface), while the internal details stay hidden. Code that uses the object depends only on that interface, so the implementation can change without affecting it. Encapsulation, which bundles data with its methods and restricts access, supports the same hiding.

Answer (a)

Why not others:

•(b) — a subclass taking over attributes and behaviors from its superclass is inheritance
•(c) — several methods with the same name but different parameter lists is overloading
•(d) — a subclass redefining a superclass method with the same name and parameters is overriding, the basis of runtime polymorphism

Key rule: Inheritance reuses a superclass, overloading varies the parameters, overriding varies the implementation, and abstraction exposes only the essential interface.

System Development Technology · AI-written, may contain errors

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