The feature by which a new class acquires the properties and behaviour of an existing class is
- A.Inheritance
- B.Polymorphism
- C.Abstraction
- D.Message passing
Correct answer
Explanation
The correct answer is A, Inheritance. Inheritance lets a derived, child or sub class take the members of a base, parent or super class and add its own, which is the main route to code reuse in object-oriented programming; its forms are single, multiple, multilevel, hierarchical and hybrid. Option B is wrong because polymorphism is one name behaving in many forms, obtained through overloading and overriding. Option C is wrong because abstraction is the hiding of implementation detail behind an essential interface. Option D is wrong because message passing is simply one object calling the method of another object. Remember the language difference asked with this feature: C++ allows multiple inheritance with classes while Java does not and uses interfaces instead. Also keep the vocabulary ready, because questions use it interchangeably: base, parent or super class for the old one, and derived, child or sub class for the new one.
Read the full article: Object-Oriented Programming: Classes, Objects and Pillars
Practice Questions
View allWhich of the following is regarded as the first object-oriented programming language?
- A.Simula 67
- B.FORTRAN
- C.COBOL
- D.BASIC
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Simula 67, designed by Ole-Johan Dahl and Kristen Nygaard, introduced the ideas of class, object and inheritance and is therefore treated as the first object-oriented language, from which C++ and Java later borrowed.
Read the full explanation →Which of the following is NOT counted among the four basic features of object-oriented programming?
- A.Abstraction
- B.Inheritance
- C.Recursion
- D.Polymorphism
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Recursion is a general programming technique in which a function calls itself, and it works equally well in procedural languages such as C, so it is not a feature of the object-oriented approach.
Read the full explanation →Wrapping up of data and the functions that operate on that data into a single unit is called
- A.Inheritance
- B.Encapsulation
- C.Overloading
- D.Compilation
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Encapsulation means binding the data members and the member functions that act on them inside one unit, the class, and keeping the data private so that it can be reached only through the methods provided; the standard illustration is a capsule holding the medicine inside it.
Read the full explanation →Showing only the essential features of an object to the user while hiding its internal details is known as
- A.Abstraction
- B.Encapsulation
- C.Inheritance
- D.Instantiation
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Abstraction presents only what the user needs, such as the accelerator and brake of a car, and keeps the internal working out of sight; in C++ it is obtained through abstract classes with pure virtual functions and in Java through interfaces and abstract classes.
Read the full explanation →Who developed the C++ programming language?
- A.Dennis Ritchie
- B.James Gosling
- C.Bjarne Stroustrup
- D.Guido van Rossum
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Bjarne Stroustrup developed the language at Bell Laboratories, starting it as C with Classes and giving it the name C++ in 1983; it adds classes, inheritance and polymorphism to C while keeping C procedural power, which is why it is called a hybrid language.
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