Java Reference
In-Depth Information
Next we discuss the other decision-making control structure in Java: the
switch
statement.
The
switch
Statement
The exam objectives state that you should be able to “develop code that implements a
switch
statement and identify legal argument types.” A
switch statement
is a decision-
making control structure based on testing an integer value for equality to a list of
case
statements. A
switch
is similar to an
if-then-else
statement, except that a
switch
statement can only test for equality and it is possible for multiple blocks of code in a
switch
to execute. Figure 3.2 shows the syntax of a
switch
statement.
The syntax of a
switch
statement
FIGURE 3.2
The switch keyword
Parentheses (required)
Beginning curly brace
switch(
integer_variable
) {
case
constantexpression
:
statements
;
case
constantexpression
:
statements
;
The body of a
switch consists
of one or more
case statements.
...
default :
statements
;
The default
block is optional
and must
appear at the
end.
}
Ending curly brace
The following rules apply to using
switch
statements:
The
integer_variable
must be compatible with an
int
, which means you can only
switch on a
byte
,
short
,
char
,
int
,
Byte
,
Short
,
Character
,
Integer
, or an enum type.
Any number of
case
statements can appear.
The
constantexpression
of a
case
must be a literal value or a
final
variable.
The
default
block is optional and must appear at the end of all the
case
statements. If
none of the
case
statements equal the expression, the
default
block executes.
When a
case
is true, no other
case
statements are tested for equality, and all
statements following the
case
execute until a
break
occurs or the end of the
switch
statement is reached.
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