In C++, enumerations are a way to create a named integer type. Prior to C++11, enumerations were declared using the traditional unscoped syntax, which could lead to naming conflicts and unwanted implicit conversions.

In C++11, the scoped enumeration feature was introduced to address these issues. Scoped enumerations, also known as enum class, provide better encapsulation and type safety guarantees in comparison to traditional unscoped enumerations.

What are Scoped Enumerations?

Scoped enumerations are declared using the enum class syntax. Unlike traditional unscoped enums, the enumerators in a scoped enumeration are not automatically placed in the enclosing scope. They are strongly typed and do not implicitly convert to integers or other enumeration types.

enum class Color { Red, Green, Blue };

Benefits of Scoped Enumerations

1. Improved Type Safety

Scoped enumerations provide stronger type checking, preventing inadvertent conversions between different enumeration types and reducing bugs related to accidental misuse of enumerations.

2. Encapsulation

The enumerators in a scoped enumeration are encapsulated within the scope of the enumeration, preventing naming conflicts with other symbols in the same scope.

3. Explicit Qualification

Access to enumerators of scoped enumerations requires explicit qualification with the enumeration type, making the code more readable and self-documenting.

Usage Example

Let’s see how scoped enumerations can be used in practice:

#include <iostream>

enum class Status { OK, Error };

void processStatus(Status status) {
    switch(status) {
        case Status::OK:
            std::cout << "Operation successful\n";
            break;
        case Status::Error:
            std::cout << "Error occurred\n";
            break;
    }
}

int main() {
    processStatus(Status::OK);
    return 0;
}

Conclusion

Scoped enumerations provide a safer and more robust way to define and use enumerations in C++. By leveraging the enum class syntax, developers can benefit from improved type safety, encapsulation, and self-documenting code.

For more information on scoped enumerations in C++, refer to the C++ reference documentation.