Enumeration Type

In this lesson, we’ll look at a data type that is defined by the user, known as the enum or enumerated type.

What is the enum data type?

Enumeration or enum type lets us assign names to integral constants. The enum keyword is used to define an enumeration. It’s just a way to name integer values. This makes our code easier to read and maintain.

We are most likely to use enums when we want to ensure that the value(s) used in the program are from within the limited set of possible values.

Syntax

enum type-name {value1, value2, ... valueN};

The type-name is the name of the enumeration. The compiler would, by default, assign the first value 0 to value1, 1 to value2, 2 to value3, and so on.

However, we can set a specific value to an enum element as well.

enum type-name {value1 = 4, value2, value3, ... valueN};

If we don’t assign any specific value to any name, it will automatically be assigned the value of their predecessor, + 1. So, value2 would be equal to 5, value3 would be equal to 6, and so on.

For example, we’ve created an enumeration type called coffee, where latte, espresso, cappuccino, americano and mocha are the values of coffee type. No other value can be part of the coffee. We’ll define it as follows:

enum coffee {latte, espresso, cappuccino, americano, mocha};

To use this enumerated type, we’ll create an enum type variable and assign it any of the enum elements (enumerators). To use the enumerated type coffee, let’s create the variable favorite:

// enum type-name variableName; 
enum coffee favorite;  

Here, favorite is the object of the enumerated type coffee. This means favorite can only have values equal to the enum elements.

A simple program that demonstrates how enums work is shown below. Click “Run” to see the output of the program.