Java Switch
Selecting from multiple options in Java
🔄 What is Java Switch?
Java Switch statement allows you to choose from multiple options based on a variable's value. It's a cleaner alternative to multiple if-else statements when comparing one variable.
// Simple switch statement
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;
default: System.out.println("Other day");
}
Output:
Wednesday
Switch Statement Components
Switch Expression
Variable to compare against cases
switch (variable) {
// cases here
}Case Labels
Possible values to match
case 1:
System.out.println("One");
break;Break Statement
Exit the switch block
case 2:
System.out.println("Two");
break; // Important!Default Case
Fallback when no case matches
default:
System.out.println("Other");
break;🔹 Basic Switch Example
Using switch to handle different day numbers:
public class SwitchExample {
public static void main(String[] args) {
int dayNumber = 5;
String dayName;
switch (dayNumber) {
case 1:
dayName = "Monday";
break;
case 2:
dayName = "Tuesday";
break;
case 3:
dayName = "Wednesday";
break;
case 4:
dayName = "Thursday";
break;
case 5:
dayName = "Friday";
break;
case 6:
dayName = "Saturday";
break;
case 7:
dayName = "Sunday";
break;
default:
dayName = "Invalid day";
break;
}
System.out.println("Day " + dayNumber + " is " + dayName);
}
}Output:
Day 5 is Friday
🔹 Switch with Characters
Switch statements can work with characters too:
public class CharacterSwitch {
public static void main(String[] args) {
char grade = 'B';
switch (grade) {
case 'A':
System.out.println("Excellent! Score: 90-100");
break;
case 'B':
System.out.println("Good! Score: 80-89");
break;
case 'C':
System.out.println("Average! Score: 70-79");
break;
case 'D':
System.out.println("Below Average! Score: 60-69");
break;
case 'F':
System.out.println("Failed! Score: Below 60");
break;
default:
System.out.println("Invalid grade");
break;
}
}
}Output:
Good! Score: 80-89
🔹 Switch with Strings
Modern Java allows switch with String values:
public class StringSwitch {
public static void main(String[] args) {
String month = "January";
int days;
switch (month) {
case "January":
case "March":
case "May":
case "July":
case "August":
case "October":
case "December":
days = 31;
break;
case "April":
case "June":
case "September":
case "November":
days = 30;
break;
case "February":
days = 28; // Not considering leap year
break;
default:
days = 0;
System.out.println("Invalid month");
break;
}
if (days > 0) {
System.out.println(month + " has " + days + " days");
}
}
}Output:
January has 31 days
🔹 Fall-through Behavior
What happens when you forget the break statement:
public class FallThrough {
public static void main(String[] args) {
int number = 2;
System.out.println("Without break statements:");
switch (number) {
case 1:
System.out.println("One");
// No break - falls through
case 2:
System.out.println("Two");
// No break - falls through
case 3:
System.out.println("Three");
break; // Finally stops here
default:
System.out.println("Other");
}
System.out.println("\nWith proper break statements:");
switch (number) {
case 1:
System.out.println("One");
break;
case 2:
System.out.println("Two");
break;
case 3:
System.out.println("Three");
break;
default:
System.out.println("Other");
}
}
}Output:
Without break statements:
Two
Three
With proper break statements:
Two