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Revised: Mon Mar 28 13:56:51 CDT 2016
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Earlier modules have touched briefly on the topic of operators . This module discusses Java operators in depth.
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.
The first step in learning to use a new programming language is usually to learn the foundation concepts such as
This module concentrates on the operators used in Java.
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:
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 :
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) .
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