<< Chapter < Page Chapter >> Page >
Earlier modules have touched briefly on the topic of operators. This module discusses Java operators in depth.

Revised: Mon Mar 28 13:56:51 CDT 2016

This page is included in the following Books:

Table of contents

Preface

Earlier modules have touched briefly on the topic of operators . This module discusses Java operators in depth.

Viewing tip

I recommend that you open another copy of this module in a separate browser window and use the following links to easily find and view the listings while you are reading about them.

Listings

  • Listing 1 . Illustration of prefix and postfix notation.
  • Listing 2 . Illustration of relational operators.

Introduction

The first step in learning to use a new programming language is usually to learn the foundation concepts such as

  • variables,
  • operators,
  • types,
  • expressions,
  • flow-of-control, etc.

This module concentrates on the operators used in Java.

Operators

Unary and binary operators

Java provides a set of operators that can be used to perform an action on one, two, or three operands. An operator that operates on one operand is called a unary operator. An operator that operates on two operands is called a binary operator. An operator that operates on three operands is called a ternary operator.

Some operators can behave either as a unary or as a binary operator. The best known such operator is probably the minus sign (-) . As a binary operator, the minus sign causes its right operand to be subtracted from its left operand. As a unaryoperator, the minus sign causes the algebraic sign of the right operand to be changed.

A ternary operator

Java has only one operator that takes three operands. It is a conditional operator, which I sometimes refer to as a cheap if statement.

The first operand is a boolean expression, which is followed by a questionmark character (?) . The question mark is followed by a second operand, which is followed by a colon character (:) . The colon character is followed by the third operand.

If the boolean expression evaluates to true, the value of the operand following the ? is returned. Otherwise, the value of the operand following the : is returned.

An example of the syntax follows:

Ternary operator syntax

boolean expression ? value1 : value2

Overloaded operators

Unlike C++, Java does not support the creation of overloaded operators in program code. (If you don't know what this means, don't worry about it.)

Operators from previous programs

The statements in the following note box illustrate the use of the following operators from Java programs in earlier modules :

  • =
  • !=
  • +
  • (char)
Operators from previous programs int ch1, ch2 = '0'; while( (ch1 = System.in.read() ) != '#') ch2 = ch1;System.out.println("The char before the # was " + (char)ch2);

The plus and cast operators

Of particular interest in this list is the plus sign (+) and the cast operator (char) .

Get Jobilize Job Search Mobile App in your pocket Now!

Get it on Google Play Download on the App Store Now




Source:  OpenStax, Object-oriented programming (oop) with java. OpenStax CNX. Jun 29, 2016 Download for free at https://legacy.cnx.org/content/col11441/1.201
Google Play and the Google Play logo are trademarks of Google Inc.

Notification Switch

Would you like to follow the 'Object-oriented programming (oop) with java' conversation and receive update notifications?

Ask