In C++, members of a class declared as private can be accessed
- A.From anywhere in the program
- B.Only within the same class
- C.Within the class and its derived classes
- D.Only from the main function
Correct answer
Explanation
The correct answer is B, only within the same class. Private is the most restricted access specifier and is also the default for a C++ class, so private data members can be read or changed only by the member functions of that class, and by a friend function or friend class if one is declared. Option A is wrong because that describes public members, which are available to any part of the program through an object. Option C is wrong because that describes protected members, which are reachable inside the class and inside classes derived from it, but not from outside. Option D is wrong because the main function has no special privilege over a class and cannot touch private members directly. Private supports encapsulation, which is why textbooks advise keeping data private and exposing public methods.
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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