🔀 switch-case Statement in Java

When you have multiple conditions to check, writing a long chain of if-else-if statements can make your code look messy 😵.

👉 That’s where the switch-case statement comes in!
It’s like a menu card 📝 → you choose one option, and the program executes the matching block.

🧐 What is switch-case in Java?

A switch statement is used to execute one block of code out of many options, based on the value of a variable or expression.

👉 Syntax:

switch(expression) {
    case value1:
        // Code if expression == value1
        break;
    case value2:
        // Code if expression == value2
        break;
    ...
    default:
        // Code if no case matches
}

🔍 How it Works

1️⃣ The expression inside switch() is evaluated.
2️⃣ The value is compared with each case.
3️⃣ If a match is found → that block executes.
4️⃣ break stops execution after a match (otherwise code will “fall through”).
5️⃣ If no match is found → default block runs.

✅ Example 1: Day of the Week

int day = 3

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;
    default: System.out.println("Invalid day");
}

Output:

Wednesday

🚀 Why use switch-case?

✔️ Cleaner than long if-else-if chains
✔️ Easy to read & maintain
✔️ Works great for menu-driven programs, enums, strings, and numbers
✔️ Boosts performance for multiple comparisons

⚡ Popular Examples of switch-case

1️⃣ Calculator Program

int a = 10, b = 5;
char operator = '+';

switch(operator) {
    case '+': System.out.println(a + b); break;
    case '-': System.out.println(a - b); break;
    case '*': System.out.println(a * b); break;
    case '/': System.out.println(a / b); break;
    default: System.out.println("Invalid Operator");
}

2️⃣ Student Grade

char grade = 'B';

switch(grade) {
    case 'A': System.out.println("Excellent!"); break;
    case 'B': System.out.println("Good Job!"); break;
    case 'C': System.out.println("Keep Trying!"); break;
    default: System.out.println("Invalid Grade");
}

3️⃣ String in switch-case (Java 7+)

String fruit = "Apple";

switch(fruit) {
    case "Apple": System.out.println("Red Fruit"); break;
    case "Banana": System.out.println("Yellow Fruit"); break;
    case "Grapes": System.out.println("Green Fruit"); break;
    default: System.out.println("Unknown Fruit");
}

💡 Pro Tips

✅ Always use break to avoid fall-through (unless you want it intentionally).
✅ Use default to handle unexpected values.
✅ From Java 7 onwards, you can use String in switch-case.
✅ From Java 12 onwards, Java introduced Switch Expressions with -> for more concise code.

📌 Example:

int day = 5;
String result = switch(day) {
    case 1 -> "Monday";
    case 2 -> "Tuesday";
    case 3 -> "Wednesday";
    case 4 -> "Thursday";
    case 5 -> "Friday";
    case 6 -> "Saturday";
    case 7 -> "Sunday";
    default -> "Invalid day";
};
System.out.println(result);

🔑 Difference between if-else and switch-case

✅ In short:
The switch-case statement is like a decision menu 🍴 for your program. It makes your code cleaner, faster, and easier to maintain, especially when dealing with multiple options.