Java Switch

Instead of writing many if..else statements, you can use the switch statement.

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
}

How it works:

The switch expression is evaluated once.
The value of the expression is compared with the values of each case.
If there is a match, the associated block of code is executed.
The break and default keywords are optional.

Example: Weekday Name Calculation

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 exits the switch block, stopping further execution. Using break prevents unnecessary case testing and improves efficiency.

The `default` Keyword

The default keyword specifies 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"

Note: If the default statement is the last statement in a switch block, it does not require a break.

Short Hand if...Else While Loop