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Right OPTION is (B) Member functions

To explain I WOULD say: Member functions are allowed inside a class but were not present in structure concept.DATA members, static data and public access specifiers were present in STRUCTURES too.

Right answer is (C) Duplicate/Redundant data

To explain: Duplicate/Redundant data is dependent on programmer and hence can’t be guaranteed by OOP. Code reusability is done using INHERITANCE. Modularity is supported by using different code files and classes. Codes are more EFFICIENT because of FEATURES of OOP.

Correct choice is (b) FALSE

For explanation: It’s false because for a program to be PURE OO, everything must be WRITTEN inside CLASSES. If this rule is VIOLATED, the program can’t be labelled as purely OO.

Correct choice is (a) 1970’s

To EXPLAIN I would say: OOP first came into picture in 1970’s by ALAN and his TEAM. Later it was used by some programming languages and got implemented successfully, SmallTalk was first language to use PURE OOP and FOLLOWED all rules strictly.

Right answer is (d) Inheritance

The explanation is: USING inheritance we can reuse the code already written and ALSO can avoid creation of MANY new functions or VARIABLES, as that can be done one time and be REUSED, using classes.

Right option is (b) Java

The BEST EXPLANATION: Java doesn’t support all 4 types of inheritance. It doesn’t support MULTIPLE inheritance. But the multiple inheritance can be IMPLEMENTED using interfaces in Java.

Correct choice is (d) As MANY as you want

The best EXPLANATION: Any NUMBER of classes can be DEFINED inside a program, provided that their names are different. In java, if public class is PRESENT then it must have the same name as that of file.

Right option is (a) It supports usual DECLARATION of primitive data types

Easiest explanation - As JAVA supports usual declaration of data VARIABLES, it is partial implementation of OOP. Because ACCORDING to rules of OOP, object CONSTRUCTORS must be used, even for declaration of variables.

Right option is (d) OOP can be used without using any header FILE

The explanation: We NEED not include any specific header file to use OOP concept in C++, only specific functions used in code need their RESPECTIVE header files to be included or classes should be DEFINED if needed.

The CORRECT CHOICE is (a) Use of this pointer

For explanation: Use of this pointer allows an object to call data and methods of itself whenever NEEDED. This helps US call the members of an object recursively, and differentiate the variables of different scopes.

The CORRECT choice is (c) Encapsulation and Abstraction

Easy explanation - Encapsulation and Abstraction are similar features. Encapsulation is ACTUALLY binding all the properties in a single class or we can say hiding all the features of object inside a class. And Abstraction is hiding unwanted data (for user) and SHOWING only the data REQUIRED by the user of PROGRAM.

The correct option is (c) START Class

The best explanation: Only 9 TYPES of classes are provided in general, namely, abstract, final, mutable, wrapper, anonymous, input-output, string, system, network. We MAY further divide the classes into PARENT class and SUBCLASS if inheritance is used.

Right answer is (a) Private

Easiest explanation - The DATA members and MEMBER FUNCTIONS are Private by default in C++ classes, if NONE of the access specifier is used. It is actually made to increase the PRIVACY of data.

Right option is (d) Abstract class

The explanation is: Abstract classes can have MEMBER functions with no implementation, where the inheriting SUBCLASSES must implement those functions.

The correct ANSWER is (d) Depends on access specifier and inheritance USED

To explain I would SAY: It depends on the access specifier and the type of inheritance used with the class, because if the class is inherited then the nested class can be used by subclass too, provided it’s not of private type.

Correct option is (a) True

Easy explanation - The CLASS containing main function can be INHERITED and HENCE the PROGRAM can be executed using the derived class names also in java.

The correct answer is (C) MEMBER functions NEED not be declared inside the class definition

To explain I would say: Member functions must be declared inside class body, though the definition can be GIVEN OUTSIDE the class body. There is no way to declare the member functions outside the class.

Right choice is (b) student class{ };

The best explanation: KEYWORD class should COME first. Class NAME should come after keyword class. PARAMETERIZED constructor definition depends on programmer so it can be left EMPTY also.

The CORRECT choice is (B) Class and structure

The BEST explanation: Class and structure are SIMILAR to each other. Only major difference is that a structure doesn’t have MEMBER functions whereas the class can have both data members and member functions.

Correct choice is (d) Abstract class

Easy explanation - INSTANCE of abstract class can’t be CREATED as it will not have any constructor of its own, hence while CREATING an instance of class, it can’t initialize the object members. Actually the class INHERITING the abstract class can have its instance because it will have implementation of all members.

The correct answer is (a) Instance of a class

Easy explanation - An object is instance of its class. It can be declared in the same WAY that a variable is declared, only THING is you have to USE class name as the DATA type.

Right answer is (d) As MANY as you want

The best explanation: You can create as many OBJECTS of a specific class as you want, provided enough MEMORY is AVAILABLE.

Right choice is (c) Objects can’t be passed by REFERENCE

To explain I would say: Objects can be passed by reference. Objects can be passed by value ALSO. If the object of a CLASS is not created, we can’t USE members of that class.

Right ANSWER is (C) class student{}s[];

The explanation is: The array must be specified with a size. You can’t declare object array, or any other LINEAR array without specifying its size. It’s a MANDATORY field.

The correct option is (d) Passed as function

To EXPLAIN: Object can’t be passed as function as it is an instance of some CLASS, it’s not a function. Object can be passed by reference, VALUE or copy. There is no term defined as PASS as function for objects.

The correct answer is (b) False

To EXPLAIN: Functions can always return an OBJECT if the return type is same as that of object being RETURNED. Care has to be taken while writing the PROTOTYPE of the function.

Right option is (a) Using dot OPERATOR/period symbol

Explanation: Using dot operator after the NAME of object we can access its MEMBERS. It is not necessary to use the pointers. We can’t use the names directly because it may be USED outside the class.

Correct CHOICE is (b) ABSTRACT class student{}; student s;

For explanation: We can never CREATE instance of an abstract class. Abstract classes doesn’t have constructors and hence when an instance is CREATED there is no facility to initialize its members. Option d is correct because topper class is inheriting the base abstract class student, and hence topper class object can be created easily.

Correct choice is (a) A TEMPORARY object is CREATED to return the value

The explanation: A temporary object is created to return the value. It is created because the object used in function is destroyed as SOON as the function is returned. The temporary variable returns the value and then gets destroyed.

Right choice is (C) Can’t be used by any other function

For explanation: The OBJECT declared in main() have local scope inside main() function only. It can’t be used OUTSIDE main() function. Scope RESOLUTION operator is used to access GLOBALLY declared variables/objects.

Correct answer is (B) False

For explanation: The explanation given is wrong because OBJECT can always be used with pointers like with any other VARIABLES. Compiler doesn’t have to KNOW the structure of the class to use a pointer because the pointers only POINTS to a memory address/stores that address.

The correct CHOICE is (c) class student{}S1,S2; s1=s2;

The best explanation: Only if the objects are of same class then their data can be copied from to another using assignment OPERATOR. This actually comes under operator OVERLOADING. Class constructors can’t be assigned any explicit value as in option class student{}s1; class topper{}t1; s1=t1; and class student{}s1; class topper{}t1; s1.student()=s2.topper();.

Correct option is (b) Inheritance

Easy EXPLANATION - Inheritance indicates the code reusability. Encapsulation and ABSTRACTION are meant to hide/group data into one element. POLYMORPHISM is to INDICATE different tasks performed by a single entity.

The correct answer is (C) Data may/may not be declared using object

The best I can EXPLAIN: Data must be declared using objects. Object usage is mandatory because it in turn calls its constructors, which in turn must have a class DEFINED. If object is not USED, it is a violation of pure OOP CONCEPT.

The correct option is (c) Polymorphism

Easy explanation - For the feature given above, the OOP feature used is Polymorphism. EXAMPLE of polymorphism in REAL life is a kid, who can be a student, a SON, a BROTHER depending on where he is.

Correct CHOICE is (a) PLATFORM independent

The BEST explanation: Platform INDEPENDENCE is not feature of OOP. C++ supports OOP but it’s not a platform independent language. Platform independence depends on programming language.

Right choice is (a) 7

Easy explanation - There are 7 basic features that define WHETHER a programing language is pure OOP or not. The 4 basic features are inheritance, polymorphism, encapsulation and abstraction. Further, ONE is, object use is must, SECONDLY, MESSAGE passing and lastly, Dynamic binding.

The CORRECT choice is (C) Message Passing

The best explanation: The interaction between two object is called the message passing feature. Data TRANSFER is not a feature of OOP. Also, message reading is not a feature of OOP.

Correct CHOICE is (d) Basically all the features of OOP gets violated

The BEST I can explain: All the features are violated because INHERITANCE and ENCAPSULATION won’t be implemented. Polymorphism and Abstraction are still possible in some cases, but the main features like DATA binding, object use and etc won’t be used hence the use of class is must for OOP concept.