Java Switch
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Java Switch Statements
Instead of writing many if..else statements, you can use the switch statement.
Think of it like ordering food in a restaurant: If you choose number 1, you get Pizza. If you choose 2, you get a Burger. If you choose 3, you get Pasta. Otherwise, you get nothing.
The switch statement selects one of many code blocks to be executed:
Syntax
switch(expression) {
case x:
// code block
break;
case y:
// code block
break;
default:
// code block
}
This is how it works:
- The
switch expression is evaluated once.
- The result is compared with each
case value.
- If there is a match, the matching block of code runs.
- The
break statement stops the switch after the matching case has run.
- The
default statement runs if there is no match.
The example below uses the weekday number to calculate the weekday name:
Example
int day = 4;
switch (day) {
case 1:
System.out.println("Monday");
break;
case 2:
System.out.println("Tuesday");
break;
case 3:
System.out.println("Wednesday");
break;
case 4:
System.out.println("Thursday");
break;
case 5:
System.out.println("Friday");
break;
case 6:
System.out.println("Saturday");
break;
case 7:
System.out.println("Sunday");
break;
}
// Outputs "Thursday" (day 4)
Try it Yourself »
The break Keyword
When Java reaches a break
keyword, it breaks out of the switch block.
This will stop the execution of more code and case testing inside
the block.
When a match is found, and the job is done, it's time for a break. There is no need for more testing.
A break can save a lot of execution time because it "ignores" the execution
of all the rest of the code in the switch block.
The default Keyword
The default keyword specifies some code to run if there is no
case match:
Example
int day = 4;
switch (day) {
case 6:
System.out.println("Today is Saturday");
break;
case 7:
System.out.println("Today is Sunday");
break;
default:
System.out.println("Looking forward to the Weekend");
}
// Outputs "Looking forward to the Weekend"
Try it Yourself »
Note that if the default statement is used
as the last statement in a switch block, it does not need a break.
