2.23 Jb0210: java oop: operators

Populating vacated bits for shift operations

The signed right shift operation populates the vacated bits with the sign bit, while the left shift and the unsigned right shift populate the vacated bits with zeros.

In all cases, bits shifted off the end are lost.

The rule for bitwise and

The bitwise and operation operates according to the rule that the bitwise and of two 1 bits is a 1 bit.

Any other combination results in a 0 bit.

Bitwise inclusive or

For the inclusive or , if either bit is a 1, the result is a 1.

Otherwise, the result is a 0.

Bitwise exclusive or

For the exclusive or , if either but not both bits is a 1, the result is a 1.

Otherwise, the result is a 0.

Another way to state this is if the bits are different, the result is a 1. If the two bits are the same, the result is a0.

The complement operator

Finally, the complement operator changes each 1 to a 0 and changes each 0 to a 1.

Assignment operators

Simple assignment operator

The (=) is a value assigning binary operator in Java. The value stored in memory and represented by the right operand is copied intothe memory represented by the left operand.

Using the assignment operator with reference variables

You need to be careful and think about what you are doing when you use the assignment operator with reference variables in Java. If you assign onereference variable to another, you simply end up with two reference variables that refer to the same object. You do not end up with two different objects.

(If what you need is another copy of the object, you may be able to use the clone method to accomplish that.)

Shortcut assignment operators

Java supports the following list of shortcut assignment operators. These operators allow you to perform an assignment andanother operation with a single operator.

For example, the two statements that follow perform the same operation.

Miscellaneous

This section contains a variety of miscellaneous information.

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