C++ Enumerations

Module 12: Enumerations in C++

An enumeration (enum) is a user-defined data type that represents a fixed set of named constant values. Enumerations make programs easier to read and maintain by replacing numeric constants with meaningful names.

For example, instead of using 0, 1, or 2 to represent days or colors, you can use descriptive names like Monday, Tuesday, or Wednesday.

1. enum

A traditional enum defines a group of named integer constants.

Syntax

cppCopy
1enum EnumName
2{
3    VALUE1,
4    VALUE2,
5    VALUE3
6};

Example

cppCopy
1#include <iostream>
2
3using namespace std;
4
5enum Day
6{
7    Monday,
8    Tuesday,
9    Wednesday,
10    Thursday,
11    Friday
12};
13
14int main()
15{
16    Day today = Wednesday;
17
18    cout << today;
19
20    return 0;
21}

Output

textCopy
12

By default, enumeration values start from 0.

Assigning Custom Values

You can assign custom integer values to enumeration constants.

Example

cppCopy
1#include <iostream>
2
3using namespace std;
4
5enum Status
6{
7    Success = 200,
8    NotFound = 404,
9    ServerError = 500
10};
11
12int main()
13{
14    cout << Success;
15
16    return 0;
17}

Output

textCopy
1200

2. enum class

enum class was introduced in C++11. It provides strong type safety and prevents name conflicts.

Syntax

cppCopy
1enum class EnumName
2{
3    VALUE1,
4    VALUE2
5};

Example

cppCopy
1#include <iostream>
2
3using namespace std;
4
5enum class Color
6{
7    Red,
8    Green,
9    Blue
10};
11
12int main()
13{
14    Color color = Color::Green;
15
16    if (color == Color::Green)
17    {
18        cout << "Green Selected";
19    }
20
21    return 0;
22}

Output

textCopy
1Green Selected

3. Scoped Enumeration

A scoped enumeration is another name for enum class. Its members must be accessed using the scope resolution operator (::).

Example

cppCopy
1#include <iostream>
2
3using namespace std;
4
5enum class Direction
6{
7    North,
8    South,
9    East,
10    West
11};
12
13int main()
14{
15    Direction dir = Direction::North;
16
17    if (dir == Direction::North)
18    {
19        cout << "Moving North";
20    }
21
22    return 0;
23}

Output

textCopy
1Moving North

enum vs enum class

Best Practices

• Use enum class in modern C++ projects.
• Choose meaningful names for enumeration values.
• Assign custom values only when required.
• Use scoped enumerations to avoid naming conflicts.
• Group related constants into a single enumeration.

Practice Problems

1. Create an enum for the days of the week.
2. Create an enum for months of the year.
3. Assign custom values to an enumeration.
4. Use enum class for traffic light colors.
5. Write a program that prints different messages based on an enumeration value.

Interview Questions

1. What is an enumeration in C++?
2. What are the advantages of using enum?
3. What is the difference between enum and enum class?
4. What is a scoped enumeration?
5. Why is enum class considered safer than enum?
6. Can you assign custom values to enumeration constants?
7. When should you use enum class instead of enum?

Summary

In this module, you learned:

• What enumerations are and how they improve code readability.
• How to create and use traditional enum.
• How to assign custom values to enumeration constants.
• How enum class provides strong type safety and scoped members.
• The differences between enum and enum class.
• Best practices for using enumerations in modern C++ applications.

Next Module: Module 13: Object-Oriented Programming (OOP) — Classes, Objects, Constructors, Destructors, Encapsulation, Inheritance, Polymorphism, Abstraction, Virtual Functions, Friend Functions, and Operator Overloading.