11 Lecture - Inheritance Is

  1. Home
  2. Courses
  3. Database Management System
  4. 11 Lecture

11 Lecture

CS403

Midterm & Final Term Short Notes

Inheritance Is

Inheritance is a fundamental concept in object-oriented programming where a new class is created by deriving characteristics and properties from an existing class. It allows code reuse, promotes code organization, and supports the concept of pol


Important Mcq's
Midterm & Finalterm Prepration
Past papers included

Download PDF
  1. In object-oriented programming, what is inheritance? a) A process of creating new objects b) A process of copying existing objects c) A process of deriving new classes from existing classes d) A process of extending the functionality of existing classes Answer: c) A process of deriving new classes from existing classes Which keyword is used to implement inheritance in Java? a) extends b) implements c) abstract d) final Answer: a) extends Inheritance enables: a) Code reuse b) Code duplication c) Code obfuscation d) Code obsolescence Answer: a) Code reuse Which of the following statements about inheritance is true? a) A derived class can access the private members of its base class. b) A derived class can modify the private members of its base class. c) A derived class cannot inherit the private members of its base class. d) A derived class can inherit the private members of its base class, but cannot access them. Answer: c) A derived class cannot inherit the private members of its base class. Which of the following is not a type of inheritance? a) Single inheritance b) Multiple inheritance c) Hierarchical inheritance d) Parallel inheritance Answer: d) Parallel inheritance What is the advantage of hierarchical inheritance? a) It allows multiple classes to inherit from a single base class. b) It allows a class to inherit from multiple base classes. c) It allows a class to inherit from itself. d) It allows a class to inherit from its own child class. Answer: a) It allows multiple classes to inherit from a single base class. Which of the following is not a method of implementing inheritance? a) Interfaces b) Abstract classes c) Composition d) Polymorphism Answer: c) Composition Which of the following is not a disadvantage of using inheritance? a) Tight coupling between classes b) Fragile base class problem c) Difficulty in understanding complex class hierarchies d) Code obfuscation Answer: d) Code obfuscation Which of the following statements about protected members is true? a) Protected members are accessible only within the same package. b) Protected members are accessible only within the same class. c) Protected members are accessible within the same package and in derived classes. d) Protected members are not accessible in any circumstance. Answer: c) Protected members are accessible within the same package and in derived classes. Which of the following is true about the final keyword in Java? a) It prevents a class from being inherited. b) It prevents a method from being overridden. c) It prevents a variable from being modified. d) All of the above. Answer: d) All of the above.


Subjective Short Notes
Midterm & Finalterm Prepration
Past papers included

Download PDF

  1. What is the main benefit of using inheritance in object-oriented programming? Answer: The main benefit of using inheritance is code reuse, as it allows the creation of new classes that inherit the properties and methods of existing classes. How does inheritance promote code organization in software development? Answer: Inheritance promotes code organization by allowing the creation of hierarchies of related classes, where the derived classes inherit and extend the functionality of the base class. What is the difference between single and multiple inheritance? Answer: Single inheritance allows a class to inherit properties and methods from only one base class, while multiple inheritance allows a class to inherit from more than one base class. What is the Fragile Base Class problem, and how can it be avoided? Answer: The Fragile Base Class problem occurs when changes made to the base class can break the functionality of the derived classes. It can be avoided by minimizing the number of public and protected members of the base class and by avoiding modifying the base class once it has been released. Can a derived class override a private method of its base class? Answer: No, a derived class cannot override a private method of its base class, as private methods are not visible to the derived class. What is the diamond problem in multiple inheritance, and how can it be resolved? Answer: The diamond problem occurs when two or more base classes of a derived class have a common method, leading to ambiguity in the method resolution. It can be resolved by using virtual inheritance, which ensures that only one copy of the common base class is present in the object hierarchy. How does inheritance support the concept of polymorphism? Answer: Inheritance supports polymorphism by allowing the same method to be implemented in different ways in different derived classes, and by allowing a derived class to be treated as an instance of its base class. What is the difference between public, protected, and private access modifiers in inheritance? Answer: Public members are accessible from any class, protected members are accessible within the same package and in derived classes, and private members are accessible only within the same class. Can a derived class access the private members of its base class? Answer: No, a derived class cannot access the private members of its base class. Can a base class be instantiated in inheritance? Answer: Yes, a base class can be instantiated in inheritance, but it cannot be used to create objects directly.

Inheritance is a fundamental concept in object-oriented programming that allows the creation of new classes based on existing ones. Inheritance enables code reuse and promotes code organization by allowing the creation of hierarchies of related classes, where the derived classes inherit and extend the functionality of the base class. Inheritance is implemented through the use of the "extends" keyword in Java and other programming languages. A derived class is created by specifying the base class from which it inherits, and can then add its own properties and methods, or override those of the base class. There are several types of inheritance, including single, multiple, hierarchical, and hybrid inheritance. Single inheritance allows a class to inherit properties and methods from only one base class, while multiple inheritance allows a class to inherit from more than one base class. Hierarchical inheritance allows multiple classes to inherit from a single base class, while hybrid inheritance combines two or more types of inheritance. One challenge of inheritance is the Fragile Base Class problem, which occurs when changes made to the base class can break the functionality of the derived classes. To avoid this problem, it is important to minimize the number of public and protected members of the base class and to avoid modifying the base class once it has been released. Inheritance also supports the concept of polymorphism, which allows different objects to be treated as instances of the same class. Polymorphism is achieved through the use of virtual methods, which can be overridden by derived classes to provide different implementations of the same method. Access modifiers, such as public, protected, and private, are used to control the visibility of members in inheritance. Public members are accessible from any class, protected members are accessible within the same package and in derived classes, and private members are accessible only within the same class. In conclusion, inheritance is a powerful concept in object-oriented programming that enables code reuse and promotes code organization. While it comes with some challenges, such as the Fragile Base Class problem, it offers significant benefits and is widely used in software development.

Course Lectures