Download presentation
Presentation is loading. Please wait.
Published byBlaise Moody Modified over 8 years ago
1
CPSC 233 Tutorial 5 February 9 th /10 th, 2015
2
Java Classes Each Java class contains a set of instance variables and methods Instance Variables: Type + Name Each object of a class has its own copy of the class instances.
3
Java Instance Variables public class SpeciesSecondTry { public String name; public int population; public double growthRate; public void writeOutput () { … } public int PredictPupulation (int years) { … }
4
Java Methods A method contains: Heading Name A method is invoked by its name Output Type Input Type Name Body Block {} Local Variables A series of statements defining the method functionality
5
Java Methods Output A method of a class should be invoked to: Return a value Perform a task without returning a value
6
Method Without Output Methods without Output Use the keyword void Perform some operations such as printing or changing the value for an instance variable within its block
7
Method With Output Method with output Define the type of output Use the keyword return to return the output
8
Method Input Input parameters (Formal parameters) serve as a blank space in the method These blank spaces are considered local variables for the method Input types: Primitive Types Byte – Short – Int – Long – Float – Double – Char Is String a primitive? Reference to an object Class name + Object name
9
Method Input Cont. When invoking a method using arguments, your arguments should have the same number, order and type as your formal parameters. Invoking PredictPopulation method:
10
Exercise Write a Dog class in Java with following characteristic: This class has one instance variable: Name An object of this class should be able to perform following operations: Set values for instance variable. Take the dog age as a primitive parameter and calculate the human age. Print out the instance variables and human age
11
Exercise Solution
12
Exercise cont. Write a class to test your Dog calss
13
Class Test
14
References Course Slides JAVA, An introduction to problem solving and programming
Similar presentations
© 2024 SlidePlayer.com. Inc.
All rights reserved.