Java Switch

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:

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:

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 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.

The default Keyword

The default keyword specifies some code to run if there is no case match:

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"