Constructors

1
Constructors

• Java Programming Chapter 3

2
Constructors

• Constructors are a special kind of Method that
  create an instance of your class
• Responsible for initializing your class

3
Rules for Creating Constructors

• Always shares the same name as the class
• May take parameters
• Never marked with a return type
• Written as public methods
• Use a set of initial values for the class member
  fields

4
Class Dog private int age private int
weight private Dog(int howOld, int
howBig) agehowOld weight howBig
Constructor
Set values
5
Dog

• Notice
• Dog class and constructor class have the same
  name
• Constructor has two parameters
• int howOld
• int howBig

6
Assignment

• howOld is assigned to age
• howBig is assigned to weight

7
New Dog Object

• To create an instance of a Dog object
• Combine the constructor with new operator
• Keyword new used to create a new instance of the
  class
• Dog milo new Dog(3,62)
• Arguments 3,62 are the age and weight
• Notice order is important