Attributes (OOP) (Cambridge (CIE) A Level Computer Science): Revision Note

Attributes (OOP)

What is an attribute?

• In object-oriented programming (OOP), an attribute refers to a data member or a property associated with an object or a class

• They define the state of an object and can have different values for different instances of the same class

• Attributes can be of various data types, such as integers, strings, Booleans, or even other objects

• Attributes can have different access rights

• The example below shows a Car class object with an attribute called manufacturer

• It has a private access meaning that it can be accessed only by instances of the Car class

• The data that this attribute will hold must be of the String data type

• The image below gives a visual representation of an object of this class being instantiated with a data value of “Ford” :

An example instance of an object

• In most cases each class has many different attributes

• Below is an example of an object of class "person":

Example of an object of class "person"

Programming attributes (OOP)

How do you program attributes?

Pseudocode

Example of a created class, "Person", containing several attributes

Java 

public class Person {

    // Attributes for the person class

    private String name;

    private int age;

    private String gender;

    private String occupation;

    private boolean isMarried;

}

Python

• In Python attributes are defined using the self keyword followed by the attribute name and its initial value

class MyClass:

   def __init__(self, attribute1, attribute2):

      # Define attributes

      self.attribute1 = attribute1

      self.attribute2 = attribute2