🪢Special Types
An enum is a special data type that defines a fixed set of constant values👉 {VALUE1, VALUE2, VALUE3}
To define an enum:
public enum Day {
MONDAY,
TUESDAY,
WEDNESDAY
}
To use an enum:
Day day = Day.MONDAY;
if(day == Day.MONDAY) {
😀 // Do something
}
Benefits:
📏 Defines a fixed set of values that is clear and understandable
🔒 Limits variables to only those values, increasing program integrity
🖥️ Concise and readable code using human-friendly labels vs integers
🤖 Useful for representing defined, unchanging categories like statuses, states, options
Example
public class Main {
// Define Weekday enum with constant values
public enum Weekday {
MONDAY,
TUESDAY,
WEDNESDAY,
THURSDAY,
FRIDAY,
SATURDAY,
SUNDAY
}
public static void main(String[] args) {
// Create Weekday variables using enum values
Weekday today = Weekday.WEDNESDAY;
Weekday tomorrow = Weekday.THURSDAY;
// Use enum in conditionals
if(today == Weekday.WEDNESDAY) {
System.out.println("It's the middle of the week!");
} else if(today == Weekday.SATURDAY) {
System.out.println("It's the weekend!");
}
// Invalid assignment causes compile error
Weekday invalidDay = "Tuesday";
}
}
In this example, the Weekday enum defines the valid constant values. The main method shows variable declaration, conditionals, and attempted invalid assignment with enums.
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