The Java Boutique: Java Tutorial: Java by Example: Operators and Methods

Tutorials : Java by Example : Section 2 :

Section Two Contents

Operators and Methods

Introducing the Operators

The basic operators in Java are:

Operator Explanation Example

+ adds two numbers 1 + 2

- subtracts two numbers 7 - 4

* multiplies two numbers 4 * 5

/ divides two numbers 21 / 3

For illustration, see the following example:

//Sourcecode

import java.awt.*; import java.applet.*; public class Project5D extends Applet { public void paint(Graphics g) { //two operators to do calculations with: int op1=12, op2=4; //we compute four numbers out of our two operators int sum=op1+op2; int diff=op1-op2; int prod=op1*op2; int quot=op1/op2; g.setFont(new Font("Helvetica",Font.PLAIN,18)); g.drawString(op1+" + "+op2+" = "+sum, 100,40); g.drawString(op1+" - "+op2+" = "+diff, 100,70); g.drawString(op1+" * "+op2+" = "+prod, 100,100); g.drawString(op1+" / "+op2+" = "+quot, 100,130); } }

A shorter and often used way to change variables, especially for incrementing and decrementing (adding or subtracting 1), can be seen in the following table:

Normal way (example)	Short way
x = x + 1	x++
x = x - 1	x--
x = x * 2	x*=2
x = x / 3	x/=3
x = x + 5	x+=5
x = x - 4	x-=4

Applet Index
(sorted alphabetically)
A B C D E F G H I J K
L M N O P Q R S T U
V W X Y Z #s

The Java Source
(applets w/source code)
A B C D E F G H I J K
L M N O P Q R S T U
V W X Y Z

How to Add Java Applets to Your Site

New on the Java Boutique:

New Review:

Time Management Made Easy with the Quartz Enterprise Job Scheduler
Why not just use the Java timer API? This open source scheduling API boasts simplicity, ease-of-integration, a well-rounded feature set, and it's free!

New Applet:

Reverse Complement
Reverse Complement is a simple applet that converts DNA or RNA sequences into three useful formats.