Enum

Definition

An enum (short for enumeration) is a special data type that allows a variable to be one of a set of predefined named constants. It improves code readability and enforces variable constraints to a limited set of values.

Notes:

• In C#, Java, and C++, enums are native language constructs.
• Python uses the enum module to create enums.
• JavaScript has no native enums, but you can simulate them using frozen objects.

---

C++

Syntax

enum class className {
    VALUE1,
    VALUE2,
    VALUE3
};

Example

#include <iostream>
using namespace std;

enum class Color {
    RED,
    GREEN,
    BLUE
};

void printColor(Color color) {
    switch(color) {
        case Color::RED:
            cout << "Selected color: RED" << endl;
            break;
        case Color::GREEN:
            cout << "Selected color: GREEN" << endl;
            break;
        case Color::BLUE:
            cout << "Selected color: BLUE" << endl;
            break;
    }
}

int main() {
    printColor(Color::GREEN);  // Output: Selected color: GREEN
    return 0;
}

---

C#

Syntax

enum className {
    VALUE1,
    VALUE2,
    VALUE3
}

Example

using System;

enum Color {
    RED,
    GREEN,
    BLUE
}

class Program {
    static void printColor(Color color) {
        Console.WriteLine("Selected color: " + color);
    }

    static void Main() {
        printColor(Color.GREEN);  // Output: Selected color: GREEN
    }
}

---

Java

Syntax

enum className {
    VALUE1,
    VALUE2,
    VALUE3
}

Example

enum Color {
    RED,
    GREEN,
    BLUE
}

public class Program {
    static void printColor(Color color) {
        System.out.println("Selected color: " + color);
    }

    public static void main(String[] args) {
        printColor(Color.GREEN);  // Output: Selected color: GREEN
    }
}

---

Python

Syntax

from enum import Enum

class className(Enum):
    VALUE1 = 1
    VALUE2 = 2
    VALUE3 = 3

Example

from enum import Enum

class Color(Enum):
    RED = 1
    GREEN = 2
    BLUE = 3

def print_color(color):
    print("Selected color:", color.name)

print_color(Color.GREEN)  # Output: Selected color: GREEN

---

JavaScript

Syntax

const className = Object.freeze({
    VALUE1: "VALUE1",
    VALUE2: "VALUE2",
    VALUE3: "VALUE3"
});

Example

const Color = Object.freeze({
    RED: "RED",
    GREEN: "GREEN",
    BLUE: "BLUE"
});

function printColor(color) {
    console.log("Selected color:", color);
}

printColor(Color.GREEN);  // Output: Selected color: GREEN

---

TypeScript

Syntax

enum className {
    VALUE1,
    VALUE2,
    VALUE3
}

Example

enum Color {
    RED,
    GREEN,
    BLUE
}

function printColor(color: Color): void {
    console.log("Selected color: " + Color[color]);
}

printColor(Color.GREEN);  // Output: Selected color: GREEN

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