IB Computer Science Topic D.2.2 Inheritance Revision Notes (SL/HL)

IB Computer Science Topic D.2.2 Inheritance Revision Notes (SL/HL) | RevisionDojo

Inheritance

Definition

Inheritance

An OOP principle where one class (the subclass) can reuse and extend the attributes and methods of another class (the superclass).

The Parent-Child Relationship

Parent Class (Superclass):
1. Contains common data and actions that can be shared with multiple child classes.
2. Serves as a blueprint for its subclasses.
Child Class (Subclass):
1. Inherits data and actions from the parent class.
2. Can add new features or override existing ones to provide specialised behaviour.

Analogy

Think of inheritance like a family tree.
The parent class is the ancestor, and child classes are descendants that inherit traits but can also have unique characteristics.

Example

Consider a Person class with attributes like name and age, and a method walk().
A Student class can inherit from Person, gaining these attributes and methods while adding its own, such as study().

Example

In Java, inheritance is defined via the keyword extends.

public class Dog extends Animal {
  ...
}

Here, Dog is a subclass and Animal is a superclass.

How Inheritance Works

Data inheritance:
1. Child classes inherit attributes from the parent class.
2. These attributes can be used or overridden as needed.
Action inheritance:
1. Child classes inherit methods from the parent class.

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Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Lorem ipsum dolor sit amet, consectetur adipiscing elit. Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Duis aute irure dolor in reprehenderit

Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Nemo enim ipsam voluptatem quia voluptas sit aspernatur aut odit aut fugit, sed quia consequuntur magni dolores eos qui ratione voluptatem sequi nesciunt. Neque porro quisquam est, qui dolorem ipsum quia dolor sit amet, consectetur, adipisci velit.

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat.

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

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Inheritance

Definition

Inheritance

An OOP principle where one class (the subclass) can reuse and extend the attributes and methods of another class (the superclass).

The Parent-Child Relationship

Parent Class (Superclass):
1. Contains common data and actions that can be shared with multiple child classes.
2. Serves as a blueprint for its subclasses.
Child Class (Subclass):
1. Inherits data and actions from the parent class.
2. Can add new features or override existing ones to provide specialised behaviour.

Analogy

Think of inheritance like a family tree.
The parent class is the ancestor, and child classes are descendants that inherit traits but can also have unique characteristics.

Example

Consider a Person class with attributes like name and age, and a method walk().
A Student class can inherit from Person, gaining these attributes and methods while adding its own, such as study().

Example

In Java, inheritance is defined via the keyword extends.

public class Dog extends Animal {
  ...
}

Here, Dog is a subclass and Animal is a superclass.

How Inheritance Works

Data inheritance:
1. Child classes inherit attributes from the parent class.
2. These attributes can be used or overridden as needed.
Action inheritance:
1. Child classes inherit methods from the parent class.

Definition

Paywall

(on a website) an arrangement whereby access is restricted to users who have paid to subscribe to the site.

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Note

Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam quis nostrud exercitation.

Excepteur sint occaecat cupidatat non proident

Tip

Lorem ipsum dolor sit amet, consectetur adipiscing elit.
Sed do eiusmod tempor incididunt ut labore et dolore magna aliqua.
Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris.
Duis aute irure dolor in reprehenderit in voluptate velit esse cillum.

1. System fundamentals2 subtopics

2. Computer organization1 subtopic

3. Networks1 subtopic

4. Computational thinking, problem-solving and programming3 subtopics

5. Abstract data structures (HL)1 subtopic

6. Resource management (HL)1 subtopic

7. Control (HL)1 subtopic

A. Databases4 subtopics

B. Modelling and simulation4 subtopics

C. Web science6 subtopics

D. Object-oriented programming (OOP)4 subtopics

IB Computer Science D.2.2 Inheritance Notes

1. System fundamentals2 subtopics

2. Computer organization1 subtopic

3. Networks1 subtopic

4. Computational thinking, problem-solving and programming3 subtopics

5. Abstract data structures (HL)1 subtopic

6. Resource management (HL)1 subtopic

7. Control (HL)1 subtopic

A. Databases4 subtopics

B. Modelling and simulation4 subtopics

C. Web science6 subtopics

D. Object-oriented programming (OOP)4 subtopics

Inheritance

The Parent-Child Relationship

How Inheritance Works

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account

Inheritance

The Parent-Child Relationship

How Inheritance Works

anim nostrud sit dolore minim proident quis fugiat velit et eiusmod nulla quis nulla mollit dolor sunt culpa aliqua

Duis aute irure dolor in reprehenderit

Excepteur sint occaecat cupidatat non proident

Unlock the rest of this chapter with a free account