enum_class_with_methods.cpp

Author: keineahnung2345

enum_class_with_methods.cpp

@@ -0,0 +1,51 @@
+#include <vector>
+#include <string>
+#include <map>
+#include <iostream>
+
+/**
+https://stackoverflow.com/a/53284026/10651567
+this example use a class with enum member variable to mimic 
+an enum class with methods
+**/
+
+using namespace std;
+
+class Fruit {
+public:
+    static enum Value : int {
+        APPLE = 0,
+        BANANA,
+        COCONUT
+    };
+
+    static void setupDefaultMsg() {
+        defaultMsg[APPLE] = "It's red.";
+        defaultMsg[BANANA] = "It's yellow.";
+        defaultMsg[COCONUT] = "It's hard.";
+    }
+
+    Fruit(Value v = APPLE, std::string msg = "") : value(v), customMsg(msg) { }
+    bool operator==(Fruit a) const { return value == a.value; }
+    bool operator!=(Fruit a) const { return value != a.value; }
+
+    std::string str() { return !customMsg.empty() ? customMsg : defaultMsg[value]; };
+private:
+    Value value;
+    std::string customMsg;
+    static std::map<Value, std::string> defaultMsg;
+};
+
+std::map<Fruit::Value, std::string> Fruit::defaultMsg;
+
+int main(int argc, char** argv) {
+    Fruit::setupDefaultMsg();
+
+    Fruit apple(Fruit::APPLE), banana(Fruit::BANANA);
+
+    cout << (apple == banana) << endl; // 0
+    cout << apple.str() << endl;       // It's red.
+    cout << banana.str() << endl;      // It's yellow.
+
+    return 0;
+}