Switch in Java

Why Switch?

If you have multiple conditions, using many if-else-if blocks becomes lengthy.
Switch provides a cleaner way to execute code based on a single variable’s value.

Example – Days of the Week

Using `if-else-if` (lengthy way)

int n = 1;

if (n == 1)
    System.out.println("Monday");
else if (n == 2)
    System.out.println("Tuesday");
else if (n == 3)
    System.out.println("Wednesday");
else if (n == 4)
    System.out.println("Thursday");
else if (n == 5)
    System.out.println("Friday");
else if (n == 6)
    System.out.println("Saturday");
else if (n == 7)
    System.out.println("Sunday");
else
    System.out.println("Invalid Day");

Using `switch` (better way)

int n = 1;

switch (n) {
    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;
    default:
        System.out.println("Invalid Day");
}

Key Points

1. Use of `break`

After a matching case is found, statements inside it run.
Without break, execution falls through into the next cases.

Example:

int n = 1;
switch (n) {
    case 1:
        System.out.println("Monday");
    case 2:
        System.out.println("Tuesday");
}

👉 Output:

Monday
Tuesday

(because no break after case 1)

2. Use of `default`

Acts like an else block.
Executes if no case matches.

int n = 9;

switch (n) {
    case 1:
        System.out.println("Monday");
        break;
    default:
        System.out.println("Invalid Day");
}

👉 Output: Invalid Day

Summary

switch is cleaner than multiple if-else-if.
Always use break to prevent fall-through.
default ensures safe handling of invalid inputs.

Switch in Java

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