objects-oop

Objects (OOP)

What is an object?

• An object is a representation of a real-world entity eg teacher, aeroplane, mobile phone, cat etc

• A class is like a blueprint that describes the properties and behaviours of objects, while an object is a specific instance created based on that blueprint with its own unique values for the properties

• A constructor is a special method within a class that is automatically called when an object of that class is created (instantiated)

• Constructors typically define the initial values of instance variables and perform any necessary setup to prepare the object for use

Example of 2 objects belonging to a class

Programming objects (OOP)

How do you program an object?

Pseudocode

Pseudocode for the class ‘person’ and instantiating two objects

Java

//creating the person class public class Person { // creating 4 attributes for the person class private String firstName; private String surname; private String dateOfBirth; private String hobbies; // Constructor -This creates objects of the person class public Person(String firstName, String surname, String dateOfBirth, String hobbies) { this.firstName = firstName; this.surname = surname; this.dateOfBirth = dateOfBirth; this.hobbies = hobbies; } //Creating Objects (Instances) of the person class Person person1 = new Person("Bob", "Jones", "06/10/1981", “E Sports”); Person person2 = new Person("Jess", "Jones", "05/04/1980", “Astronomy”);

Python

#creating the person class class Person: #Constructor -This creates objects of the person class def __init__(self, firstName, surname, dateOfBirth, hobbies): self.firstName = firstName self.surname = surname self.dateOfBirth = dateOfBirth self.hobbies = hobbies #Creating Objects (Instances) of the person class person1 = Person("Bob", "Jones", "06/10/1981", "E Sports") person2 = Person("Jess", "Jones", "05/04/1980", "Astronomy")