Enum
An enum, short for enumeration, is a user-defined data type in C++ used to assign names to integral constants. Enums make the code more readable and maintainable by giving meaningful names to a set of related values.
There are two types of enums in C++:
Traditional C-style enums (introduced in C and carried over to C++)
Enum classes (introduced in C++11)
Let's look at both:
Traditional C-style enums:
enum Color {
RED, // 0
GREEN, // 1
BLUE // 2
};
Color myColor = GREEN;
Key points:
By default, the first enumerator is assigned the value 0, and each subsequent enumerator is incremented by 1.
You can assign specific values to enumerators:
enum Color { RED = 5, GREEN = 10, BLUE = 15 };
Enumerators are in the same scope as the enum, which can lead to name conflicts.
They implicitly convert to integers.
Enum classes (C++11 and later):
enum class Fruit : unsigned int {
APPLE,
BANANA,
ORANGE
};
Fruit myFruit = Fruit::BANANA;
Key points:
Enum classes provide stronger type safety.
They don't implicitly convert to integers.
Enumerators are scoped within the enum class.
You can specify the underlying type (e.g., unsigned int).
Here's a more comprehensive example demonstrating both types:
#include <iostream>
// Traditional enum
enum Color {
RED,
GREEN,
BLUE
};
// Enum class
enum class Direction : char {
NORTH = 'N',
EAST = 'E',
SOUTH = 'S',
WEST = 'W'
};
int main() {
// Using traditional enum
Color paint = GREEN;
int colorCode = paint; // Implicit conversion to int
std::cout << "Color code: " << colorCode << std::endl;
// Using enum class
Direction way = Direction::EAST;
// std::cout << way; // This would not compile
std::cout << "Direction: " << static_cast<char>(way) << std::endl;
// Comparison
if (paint == GREEN) {
std::cout << "The paint is green." << std::endl;
}
if (way == Direction::EAST) {
std::cout << "We're heading east." << std::endl;
}
return 0;
}
Try it here.
Benefits of using enums:
Improved code readability
Type safety (especially with enum classes)
Easy to maintain and modify related constants
Enum classes are generally preferred in modern C++ due to their stronger type safety and scoping rules. However, traditional enums are still widely used, especially in code bases that need to maintain compatibility with C or older C++ standards.
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