Day 7: Understanding Java `switch` Case Statements

What is a switch Statement?

A switch statement is used to execute one block of code based on the value of an expression.

Instead of checking multiple conditions using if–else, we can use switch when:

• We compare one value
• Against multiple fixed values

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Data Types Supported in switch

switch supports:

• byte, short, int, char
• String

(Other types like long, float, double, and boolean are not used here.)

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=> Usage of break in switch

break is used to stop the execution of a switch case once a matching case is found.

• Without break, Java will continue executing the next cases (called fall-through)
• With break, Java exits the switch block immediately

In simple words:

break tells Java: “Stop here and come out of the switch.”

Traditional switch Case (Using break)

This is the basic and commonly used form of switch.

=> Example:

String mark = "Karthick";

switch (mark) { // Expression
    case "abc":
        System.out.println("A grade");
        break;
    case "xyz":
        System.out.println("B grade");
        break;
    case "asd":
        System.out.println("C grade");
        break;
    case "klo":
        System.out.println("D grade");
        break;
    default:
        System.out.println("Fail");
}

=> Explanation:

• The switch checks the value of mark
• If it matches a case, that block runs
• break stops execution from falling into the next case
• default runs when no case matches

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=> Usage of default in switch

default is executed when none of the case values match the switch expression.

• It acts like an else condition
• It is optional but recommended

In simple words:

default handles unexpected or unmatched values.

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=> Enhanced switch Case (Arrow -> Style)

Java also provides a simpler and cleaner syntax using the arrow (->).

=> Example:

String mark = "Karthick";

switch (mark) {
    case "abc" -> System.out.println("A grade");
    case "xyz" -> System.out.println("B grade");
    case "asd" -> System.out.println("C grade");
    case "klo" -> System.out.println("D grade");
    default -> System.out.println("Fail");
}

=> Benefits:

• No need to write break
• Code is shorter and more readable
• Reduces mistakes

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=> switch as an Expression (Returning a Value)

In modern Java, switch can also return a value and store it in a variable.

=> Example:

String result = switch (mark) {
    case "abc" -> "A grade";
    case "xyz" -> "B grade";
    case "asd" -> "C grade";
    case "klo" -> "D grade";
    default -> "Fail";
};

Here:

• The switch returns a value
• The result is stored in the variable result
• This makes the code more compact and clean

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When to Use switch

Use switch when:

• You compare one variable
• With multiple known values
• You want better readability than long if–else chains

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➡️ When Was switch Introduced in Java?

• The switch statement was introduced in Java 1.0
• Year: 1996

At that time, switch supported only:

• byte
• short
• int
• char

➡️ When Did Java Allow String in switch?

• String was allowed inside switch from Java 7
• Year: 2011

From Java 7 onwards, we can write:

switch (name) {
    case "abc":
        System.out.println("A grade");
}

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➡️ When was Arrow introduced in Java?

• Enhanced switch with -> (arrow syntax) came in Java 14
• It removed the need for break and made code cleaner

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📝 Short-Note

• break → exits the switch
• default → runs when no case matches
• switch introduced → Java 1.0 (1996)
• String in switch → Java 7 (2011)