Using scoped enumerations

Enumeration is a basic type in C++ that defines a collection of values, always of an integral underlying type. Their named values, that are constant, are called enumerators. Enumerations declared with keyword enum are called unscoped enumerations and enumerations declared with enum class or enum struct are called scoped enumerations. The latter ones were introduced in C++11 and are intended to solve several problems of the unscoped enumerations.

How to do it...

• Prefer to use scoped enumerations instead of unscoped ones.
• In order to use scoped enumerations, you should declare enumerations using enum class or enum struct:

        enum class Status { Unknown, Created, Connected };
        Status s = Status::Created;

Note

The enum class and enum struct declarations are equivalent, and throughout this recipe and the rest of the book, we will use enum class.

How it works...

Unscoped enumerations have several issues that are creating problems for developers:

• They export their enumerators...