Test: Class And Objects - 2 - Back-End Programming MCQ

For making a method as pure virtual function, We have to append ‘=0' to the class or method.

• Every class containing abstract method must be declared abstract. Correct Declaration is required.
• Abstract class can directly be initiated with ‘new’ operator. No it can’t be initiated directed by only ‘new’ operator. So, it is Inorrect
• Abstract class can be initiated. Correct
• Abstract class does not contain any definition of implementation. Correct
So, option (B) is correct.

As the name itself implies, it have to depend on other class only.

It is possible to define a class within a class termed as nested class. There are two types of nested classes.
1 – Outer class will use argument of inner class.
2 – Inner and outer class are independent to each other.(different argument)
So, optioin (A) is correct.

• Data members in C++ is inherited in a derived class from base class
• Constructor is a member function of a class which initializes objects of a class. In C++,Constructor is automatically called when object(instance of class) create.It is special member function of the class.
• Destructor is a member function which destructs or deletes an object.
• Virtual methods is a method which is redefined(Over-riden) in derived class.
So, option (C) is correct.

Destructors are automatically invoked when a object goes out of scope or when a dynamically allocated object is deleted. Inheritance does not change this behavior. This is the reason a derived destructor cannot invoke its base class destructor.

In C++, the default access is private. Since x is a private member of Test, it is compiler error to access it outside the class.

If we invoked the interface as public means, We can access the program from other programs also.

For a compiler where pointers take 4 bytes, the statement “sizeof(Test *)” returns 4 (size of the pointer ptr).
The statement “sizeof(t)” returns 8. Since static is not associated with each object of the class, we get (8 not 12).

Class hierarchies promote reuse in two ways. They are code sharing and interface sharing.

A member function can access it’s class member variables, irrespective of the access specifier in which the member variable is declared.So, a member function can always access the data in the class of which it is a member.
So, option (A) is correct.

In C++ class template and function template are similar in the way the are initiated.
Class template are not used for storage class. Class templates and function templates are instantiated in the same way and Class template is not initiated by defining an object using the template.
So (2), (3), (4) are not correct in C++.
So, option (C) is correct.

Clog is an object of class ostream that represents the standard logging stream. It is associated with the cstdio stream stderr, like cerr.

• Composition is a strong type of association between two classes with full ownership. Correct.
• Composition is a strong type of association between two classes with partial ownership. Incorrect
• Composition is a weak type of association between two classes with partial ownership. Incorrect
• Composition is a weak type of association between two classes with strong ownership. Incorrect
So, option (A) is correct.

We can make user-defined types with streams by overloading the insertion operator (<<) to put objects into streams and the extraction operator (>>) to read objects from streams.

• When a method in a subclass has the same name and type signatures as a method in the superclass, then the method in the subclass overrides the method in the superclass.
• Overloading allows different methods to have same name, but different signatures where signature can differ by number of input parameters or type of input parameters or both. Overloading is related to compile time (or static) polymorphism..
• Friend Class A friend class can access private and protected members of other class in which it is declared as friend..
• The capability of a class to derive properties and characteristics from another class is called Inheritance.
So, option (D) is correct.