C++ Enumerations

enum

An enumeration defines a named set of integer constants, making code more readable than magic numbers.

#include <iostream>
using namespace std;

enum Direction { NORTH, EAST, SOUTH, WEST };
// NORTH=0, EAST=1, SOUTH=2, WEST=3

int main() {
    Direction d = NORTH;
    if (d == NORTH) cout << "Heading North!" << endl;

    // Custom values
    enum Status { PENDING=1, ACTIVE=2, INACTIVE=3, DELETED=99 };
    Status s = ACTIVE;
    cout << "Status code: " << s << endl;   // 2
    return 0;
}

enum class (C++11 — Scoped Enum)

enum class prevents name collisions and implicit conversions to int:

enum class Color { RED, GREEN, BLUE };
enum class Fruit { RED, APPLE, BANANA };   // RED is separate from Color::RED

Color c = Color::RED;   // must use scope
// int x = Color::RED;  // ERROR — no implicit conversion

switch (c) {
    case Color::RED:   cout << "Red"   << endl; break;
    case Color::GREEN: cout << "Green" << endl; break;
    case Color::BLUE:  cout << "Blue"  << endl; break;
}

#include <iostream>
using namespace std;

enum class Season { SPRING, SUMMER, AUTUMN, WINTER };

string getTemp(Season s) {
    switch (s) {
        case Season::SPRING: return "~20°C";
        case Season::SUMMER: return "~35°C";
        case Season::AUTUMN: return "~15°C";
        case Season::WINTER: return "~5°C";
    }
    return "Unknown";
}

int main() {
    cout << "Summer: " << getTemp(Season::SUMMER) << endl;
    cout << "Winter: " << getTemp(Season::WINTER) << endl;
    return 0;
}

Summary

• enum creates named integer constants.
• enum class (scoped enum) prevents name collisions and is type-safe.
• Always prefer enum class in modern C++ code.