Assignment Operators - Java Tutorial 5.0 英文版

Start of Tutorial > Start of Trail > Start of Lesson

Search Feedback Form

Assignment Operators

You use the basic assignment operator, =, to assign one value to another. The MaxVariablesDemo program uses = to initialize all of its local variables.

//integers
byte largestByte = Byte.MAX_VALUE;
short largestShort = Short.MAX_VALUE;
int largestInteger = Integer.MAX_VALUE;
long largestLong = Long.MAX_VALUE;

//real numbers
float largestFloat = Float.MAX_VALUE;
double largestDouble = Double.MAX_VALUE;

//other primitive types
char aChar = 'S';
boolean aBoolean = true;

The Java programming language also provides several shortcut assignment operators that allow you to perform an arithmetic, shift, or bitwise operation and an assignment operation all with one operator. Suppose you want to add a number to a variable and assign the result back into the variable, as follows.

i = i + 2;

You can shorten this statement using the shortcut operator +=.

i += 2;

The previous two lines of code are equivalent.

The following table lists the shortcut assignment operators and their lengthy equivalents.

Shortcut Assignment Operators

Operator	Use	Description
+=	op1 += op2	Equivalent to op1 = op1 + op2
-=	op1 -= op2	Equivalent to op1 = op1 - op2
*=	op1 *= op2	Equivalent to op1 = op1 * op2
/=	op1 /= op2	Equivalent to op1 = op1 / op2
%=	op1 %= op2	Equivalent to op1 = op1 % op2
&=	op1 &= op2	Equivalent to op1 = op1 & op2
|=	op1 |= op2	Equivalent to op1 = op1 | op2
^=	op1 ^= op2	Equivalent to op1 = op1 ^ op2
<<=	op1 <<= op2	Equivalent to op1 = op1 << op2
>>=	op1 >>= op2	Equivalent to op1 = op1 >> op2
>>>=	op1 >>>= op2	Equivalent to op1 = op1 >>> op2

Start of Tutorial > Start of Trail > Start of Lesson

Search Feedback Form

Copyright 1995-2005 Sun Microsystems, Inc. All rights reserved.