The switch Statement

The switch statement is used when you want to compare a single variable against multiple constant values and run a block of code based on a match.

Key Points:

• The switch checks the value of a variable once, and compares it against multiple case labels.
• Use break to exit the switch after a match (avoids fall-through).
• The default block is optional and runs if no case matches.

Syntax:

switch (expression) {
    case value1:
        // code
        break;
    case value2:
        // code
        break;
    ...
    default:
        // default code
}

• The expression used in a switch must be of a specific type: It can only be a byte, short, int, char, enum, or String (String is allowed from Java 7 onwards).

  ! You cannot use types like float, double, or boolean in a switch.

• If you don’t use break after a case, Java will keep running the next case statements — even if they don’t match. This behavior is called fall-through.

  ! To stop the flow after a case block runs, you must use break.

Example 1: With break (Normal Usage)

class ShikshaSanchar {
  public static void main(String[] args) {
    int day = 2;
    switch (day) {
      case 1:
        System.out.println("Monday");
        break;
      case 2:
        System.out.println("Tuesday");
        break;
      case 3:
        System.out.println("Wednesday");
        break;
      default:
        System.out.println("Other day");
    }
  }
}

Example 2: Without break (Fall-Through Behavior)

class ShikshaSanchar {
  public static void main(String[] args) {
    int day = 2;
    switch (day) {
      case 1:
        System.out.println("Monday");
      case 2:
        System.out.println("Tuesday");
      case 3:
        System.out.println("Wednesday");
      default:
        System.out.println("Other day");
    }
  }
}

Multiple Cases, One break (Grouped Cases)

class ShikshaSanchar {
  public static void main(String[] args) {
    int day = 6;
    switch (day) {
      case 6:
      case 7:
        System.out.println("Weekend");
        break;
      case 1:
      case 2:
      case 3:
      case 4:
      case 5:
        System.out.println("Weekday");
        break;
      default:
        System.out.println("Invalid day");
    }
  }
}

Summary: