Methods

• What is a Method? 

  • Methods are fundamental in object-oriented programming (OOP) and are functions associated with objects or classes that define the behaviour and actions that objects can perform 
  • There are two main types of methods: 
  • A function 
  • A function performs a task and returns a value 
  • A procedure 
  • A procedure performs a task buts does nor return a value 
  • For example, there are many different types of aircraft which all differ in design, but all require a ‘take off’ and ‘landing’ method 
• Methods image

  
• Methods #2

  • Each object that is created from the aircraft class will have: 
  • A manufacturer value to determine the company that created the aircraft 
  • A model name for the type of aircraft 
  • A value for passenger capacity to determine how many people it can carry 
  • A speed value to determine its maximum speed
• Methods #3

  • Any objects that are created for the aircraft class also have access to the following Methods: 
  • A take off method to get the plane airborne 
  • A land method to land the plane safely 
  • A bank left method to allow the plane to turn to the left 
  • A bank right method to allow the plane to tur to the right 
• Methods #4

  • As you can imagine, for an aircraft there would be many more methods that could be implemented such emergency landing and altitude cruising actions 
  • Once objects have been created, they can use the methods from within their class by using the dot (.) notation 
  • As these methods are associated with objects, they are called instance methods 
  • For example if an object has been created as below: 
  • jumboJet = new aircraft (“Boeing”, ”747”, 416, 547) 
  • It can use methods by doing the following: 
  • Objectname.Methodname: 
  • For example:    jumboJet.Takeoff() 
• Public vs Private Methods