set-3

Answer: 1) To destroy an object when the lifetime of the object ends

Explanation:

• A destructor is used to:
  • Release resources (e.g., memory, file handles) allocated to an object.
  • Perform cleanup tasks when the object goes out of scope or is explicitly deleted.
• Therefore, the correct answer is To destroy an object when the lifetime of the object ends.

Answer: 4) ~

Explanation:

• A destructor is preceded by the tilde symbol (~).

• For example:

  class MyClass {
  public:
      ~MyClass() {
          cout << "Destructor called!";
      }
  };

• Therefore, the correct answer is ~.

Answer: 4) All of the Above

Explanation:

• All the statements are correct:
  • A constructor has the same name as the class.
  • A destructor has the same name as the class but is preceded by a tilde (~).
  • Both constructors and destructors are member functions of the class.
• Therefore, the correct answer is All of the Above.

Answer: 2) Destructor

Explanation:

• When an object goes out of scope, its destructor is automatically called to clean up resources.
• Therefore, the correct answer is Destructor.

Answer: 1) Destructor

Explanation:

• A destructor can be declared as virtual to ensure proper cleanup of derived class objects when deleted through a base class pointer.
• Constructors and data members cannot be declared as virtual.
• Therefore, the correct answer is Destructor.

Answer: 1) Default

Explanation:

• A default constructor is either:
  • A constructor with no parameters.
  • A constructor where all parameters have default values.
• Therefore, the correct answer is Default.

Answer: 1) 1

Explanation:

• Only one default constructor can exist per class.
• If multiple constructors are defined, only one can be the default constructor.
• Therefore, the correct answer is 1.

Answer: 1) 0

Explanation:

• A destructor does not take any arguments. It is called automatically when an object goes out of scope.
• Therefore, the correct answer is 0.

Answer: 1) Only once

Explanation:

• A constructor is called only once when an object is created.
• Therefore, the correct answer is Only once.

Answer: 2) Stack

Explanation:

• Local variables are stored in the stack, which is a memory area used for function calls and local data.
• Therefore, the correct answer is Stack.

Answer: 3) Void *

Explanation:

• The malloc() function returns a void pointer (void*), which can be cast to any data type.

• For example:

  int* ptr = (int*)malloc(sizeof(int));

• Therefore, the correct answer is Void *.

Answer: 4) Both A & B

Explanation:

• Both malloc and calloc are used to allocate memory dynamically:
  • malloc allocates memory without initializing it.
  • calloc allocates memory and initializes it to zero.
• Therefore, the correct answer is Both A & B.

Answer: 2) Delete

Explanation:

• The delete operator is used to release memory allocated using new in C++.

• For example:

  int* ptr = new int;
  delete ptr;

• Therefore, the correct answer is Delete.

Answer: 2) Delete

Explanation:

• In C++, the delete operator is used to free memory allocated for an object using new.
• The free function is used in C, not C++.
• Therefore, the correct answer is Delete.

Answer: 3) The ‘this’ pointer is accessible only within non-static functions

Explanation:

• The this pointer is a hidden pointer available in all non-static member functions of a class.
• It points to the object for which the member function is called.
• Therefore, the correct answer is The 'this' pointer is accessible only within non-static functions.

Answer: 2) Guard against self-reference

Explanation:

• The this pointer is used to:
  • Avoid ambiguity between class members and function parameters with the same name.
  • Guard against self-reference in assignment operations.
• Therefore, the correct answer is Guard against self-reference.

Answer: 2) Non-Modifiable

Explanation:

• The this pointer is a constant pointer, meaning its value cannot be changed.
• Therefore, the correct answer is Non-Modifiable.

Answer: 3) Both A & B

Explanation:

• The this pointer can be:
  • Const: When used in a const member function.
  • Volatile: When used in a volatile member function.
• Therefore, the correct answer is Both A & B.

Answer: 3) Only the static members of a class

Explanation:

• Static member functions can only access static data members and other static member functions of the class.
• They cannot access non-static members directly.
• Therefore, the correct answer is Only the static members of a class.

Answer: 1) Created and initialized only once

Explanation:

• Static members are:
  • Created and initialized only once when the program starts.
  • Shared among all objects of the class.
• Therefore, the correct answer is Created and initialized only once.

Answer: 4) All of the Above

Explanation:

• All the statements are correct:
  • Static data members cannot be declared as mutable.
  • Static data members can be initialized within the class if they are declared as inline.
  • Static members (functions and data) can be accessed without creating an object of the class.
• Therefore, the correct answer is All of the Above.

Answer: 1) Function Declaration

Explanation:

• The friend keyword is used in the function declaration inside the class to grant access to private and protected members.
• It is not used in the function definition or other parts of the program.
• Therefore, the correct answer is Function Declaration.

Answer: 4) All of the Above

Explanation:

• All the statements are correct:
  • Friend functions are not member functions and can be invoked like normal functions.
  • Friend functions can access private and protected members of the class directly.
  • Friend functions can be declared in the private or public section of the class.
• Therefore, the correct answer is All of the Above.

Answer: 2) Friend class

Explanation:

• The correct syntax for declaring a friend function is:

  friend returnType functionName(parameters);

• For example:

  class MyClass {
  private:
      int data;
  public:
      friend void display(MyClass obj);
  };

• Therefore, the correct answer is Friend class.

Answer: 2) Two operands

Explanation:

• A binary operator operates on two operands.
• Examples include +, -, *, /, ==, etc.
• Therefore, the correct answer is Two operands.

Answer: 3) -

Explanation:

• A unary operator operates on a single operand.
• Examples include - (negation), ++, --, !, etc.
• Therefore, the correct answer is -.

Answer: 4) All of the Above

Explanation:

• All the given operators are binary operators:
  • & (bitwise AND)
  • == (equality)
  • / (division)
• Therefore, the correct answer is All of the Above.

Answer: 1) ?:

Explanation:

• The ternary operator is ?:.

• It takes three operands and is used as a shorthand for if-else statements.

• For example:

  int result = (a > b) ? a : b;

• Therefore, the correct answer is ?:.

Answer: 2) Type casting

Explanation:

• C-style type casting is also known as type casting.

• It uses the syntax:

  (type) expression;

• Therefore, the correct answer is Type casting.

Answer: 2) 3

Explanation:

• The three major ways to perform explicit conversion in C++ are:
  1. C-style casting: (type) expression
  2. Static casting: static_cast<type>(expression)
  3. Reinterpret casting: reinterpret_cast<type>(expression)
• Therefore, the correct answer is 3.

Answer: 1) 0

Explanation:

• A conversion operator does not take any parameters.
• It is used to convert an object of one type to another type.
• Therefore, the correct answer is 0.

Answer: 1) Unary

Explanation:

• A cast operator is a unary operator because it operates on a single operand.
• Therefore, the correct answer is Unary.

Answer: 1) Implicit

Explanation:

• The compiler performs implicit casting automatically when data types are compatible.

• For example:

  int x = 10;
  double y = x; // Implicit casting from int to double

• Therefore, the correct answer is Implicit.

Answer: 2) Explicit

Explanation:

• The programmer initiates explicit casting using casting operators like static_cast, dynamic_cast, etc.
• Therefore, the correct answer is Explicit.

Answer: 3) 5

Explanation:

• The five types of inheritance in C++ are:
  1. Single inheritance
  2. Multiple inheritance
  3. Multilevel inheritance
  4. Hierarchical inheritance
  5. Hybrid inheritance
• Therefore, the correct answer is 5.

Answer: 2) A class inheriting a base class

Explanation:

• Single-level inheritance occurs when a derived class inherits from a single base class.

• For example:

  class Base {};
  class Derived : public Base {};

• Therefore, the correct answer is A class inheriting a base class.

Answer: 1) JAVA

Explanation:

• Multiple inheritance is not supported by JAVA to avoid complexity and ambiguity (e.g., the diamond problem).
• C++ supports multiple inheritance.
• Therefore, the correct answer is JAVA.

Answer: 1) Interfaces Concept

Explanation:

• In JAVA, the concept of multiple inheritance is achieved using interfaces.
• A class can implement multiple interfaces, thus simulating multiple inheritance.
• Therefore, the correct answer is Interfaces Concept.

Answer: 2) Multiple

Explanation:

• The diamond problem occurs in multiple inheritance when a class inherits from two classes that both inherit from a common base class.
• This creates ambiguity in accessing the base class members.
• Therefore, the correct answer is Multiple.

Answer: 1) Base Class Constructor

Explanation:

• When a derived class object is created, the base class constructor is called first to initialize the base class part of the object.
• Then, the derived class constructor is called.
• Therefore, the correct answer is Base Class Constructor.

Answer: 4) Any type, any number of times

Explanation:

• In a single program, any type of inheritance (single, multiple, multilevel, hierarchical, hybrid) can be used any number of times.
• Therefore, the correct answer is Any type, any number of times.

Answer: 1) At least 2

Explanation:

• In single inheritance, there must be at least two classes: a base class and a derived class.
• Therefore, the correct answer is At least 2.

Answer: 1) Base class constructor

Explanation:

• In single inheritance, the base class constructor is called first when a derived class object is created.
• Therefore, the correct answer is Base class constructor.

Answer: 1) A class derived from another derived class

Explanation:

• Multilevel inheritance occurs when a class is derived from another derived class.

• For example:

  class A {};
  class B : public A {};
  class C : public B {};

• Therefore, the correct answer is A class derived from another derived class.

Answer: 3) 3

Explanation:

• Multilevel inheritance requires at least three levels: a base class, a derived class, and a further derived class.
• Therefore, the correct answer is 3.

Answer: 1) 1 class

Explanation:

• In multilevel inheritance, each class inherits from only one class.
• Therefore, the correct answer is 1 class.

Answer: 3) Code reusability

Explanation:

• The most significant feature of OOP used in multilevel inheritance is code reusability.
• Derived classes reuse the code from their base classes.
• Therefore, the correct answer is Code reusability.

Answer: 2) A class is derived from two or more classes

Explanation:

• Multiple inheritance occurs when a class is derived from two or more base classes.

• For example:

  class A {};
  class B {};
  class C : public A, public B {};

• Therefore, the correct answer is A class is derived from two or more classes.

Answer: 3) 3

Explanation:

• To implement multiple inheritance, a program must contain at least three classes: two base classes and one derived class.
• Therefore, the correct answer is 3.