Java Reference
In-Depth Information
break; //optional
case value :
//Statements
break; //optional
//You can have any number of case statements.
default : //Optional
//Statements
}
The following rules apply to a switch statement:
The variable used in a switch statement can only be an integer value
32 bits or smaller. That means the only data types that can be switched
on are byte, short, int, and char.
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You can have any number of case statements within a switch. Each case
is followed by the value to be compared to and a colon.
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The value for a case must be the same data type as the variable in the
switch, and it must be a constant or a literal.
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When the variable being switched on is equal to a case, the statements
following that case will execute until a break is reached.
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When a break is reached, the switch terminates, and the flow of control
jumps to the next line following the switch statement.
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Not every case needs to contain a break. If no break appears, the flow of
control will “fall through” to subsequent cases until a break is reached.
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A switch statement can have an optional default case , which must appear
at the end of the switch. The default case can be used for performing a
task when none of the cases is true. No break is needed in the default
case.
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I always find it is easier to understand a switch by going through an exam-
ple. The following CongratulateStudent program contains a switch statement
that prints out a message to a student, depending on the student's letter grade.
The first statement within main() retrieves the first character from the first
command-line argument, which is supposed to be the student's letter grade.
Study the switch statement and try to determine what the output will be for
the various possible values of grade. Figure 3.3 shows some sample outputs of
the program.
public class CongratulateStudent
{
public static void main(String [] args)
{
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