Java Reference
In-Depth Information
switch( variable ){
variable =1
variable =2
case 1: ....
case 2: ....
variable = 3
case 3: ....
variable is not 1, 2, or 3
default ....
FIGURE 2.9: The switch statement.
A switch statement can only be used to substitute a set of if statements that
check for equality . We cannot use an if statement to check for inequality (e.g., > =3).
Java supports a switch statement only on variables of type int , char ,and String .
Java does not support a switch statement on doubles.
A switch statement checks the value of the variable inside the parentheses. If it is equal
to the first case value, then the program jumps to this case and continues executing. Usually,
a break statement is put at the end of every case block in order to guarantee that only
one case statement is executed. For example, if the break statements are removed from the
above code and the user enters the string “A”, then all print statements will be executed.
The break statement exits out of the current switch statement and goes to the
first line immediately after the switch block. Usually, a break statement is required
at the end of each case blockinorderforthe switch statement to work properly.
A break statement is not required after the last switch block (assuming there is no
default block) because the program exits the switch statement after that anyway.
Note that the switch syntax allows a default option. In the above code, if the input
string is not equal to "A" , "B" , "C" , "D" ,or "F" , then only the last print statement will be
2.7 The Conditional Operator
It seems tedious to use an if-else construct even when we have a single line in both
the if and else blocks. In some cases, Java allows us to substitute the if-else statement
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