JavaSwitch
Java Switch Statements
Instead of writingmanyif..else statements, you can use theswitch 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.
Theswitch 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
switchexpression is evaluated once. - The result is compared with each
casevalue. - If there is a match, the matching block of code runs.
- The
breakstatement stops the switch after the matching case has run. - The
defaultstatement 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)The break Keyword
When Java reaches abreak 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
Thedefault 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"Note that if thedefault statement is used as the last statement in a switch block, it does not need a break.
