Java style enums in C++

Question

In Java, I can work with enums like classes. For example, I can create enum's constructor that take a value and init enum's value and class static function values() to list all enum's values.

How to implement this in C++?

Here is the Java code:

enum EquationType {

    LINE("LINE"), LINE3D("LINE3D"), BEZIER("BEZIER"), PLANE("PLANE");

    EquationType(String curve_type) {

        type = curve_type;

    } //END: CurveType()

    String type; // enum's member variable that store symbolic name of type (for utilite using)

    public String get_type_string() {

        return type;

    } //END: get_type_string()

    public static EquationType _bystring(String type) throws Exception {

        for (EquationType value : values()) { // search by list of enum's values

            if (value.get_type_string().equals(type.trim().toUpperCase())) {

                return value;

            }
        }

    } //END: _bystring()

} //END: enum EquationType

It creates enum with 4 members (LINE, LINE3D, BEZIER, PLANE). This enum class type have the function that return the enum's type by the string name value like EquationType._bystring("PLANE") will return EquationType.PLANE. It uses the values() function that lists all possible enum type values.

Is there some analog in C++?

I have my doubts as to whether that compiles in Java. Did you define a type called string? — Michael Francis
– Michael Francis, Commented Feb 9, 2020 at 5:49
There is no exact equivalent in C++, but there are several pretty close alternatives. In some cases an enum class will work. In this case, a full-fledged class, with some overloaded operators will probably be a closer match. In any case, unfortunately, stackoverflow.com is not a replacement for a good C++ book, and you should find complete information about doing this in any good C++ book. — Sam Varshavchik
– Sam Varshavchik, Commented Feb 9, 2020 at 5:49
So you want to get the enum value via a string and vice versa? std::unordered_map? In this case maybe you don't want to use enum at all. — Ivaylo Valchev
– Ivaylo Valchev, Commented Feb 9, 2020 at 5:51

Aykhan Hagverdili · Accepted Answer · 2020-02-09 07:18:33Z

0

#include <string>
#include <unordered_map>

enum EquationType {
  LINE, LINE3D, BEZIER, PLANE
};

int main() {
  std::unordered_map<std::string, EquationType> equationMap({
    {"LINE", LINE},
    {"LINE3D", LINE3D},
    {"BEZIER", BEZIER},
    {"PLANE", PLANE}
  });

  EquationType line = equationMap["LINE"];
}

Disclaimer: I haven't compiled this. I may have messed up the syntax.

edited Feb 9, 2020 at 7:18

Aykhan Hagverdili

30.5k6 gold badges53 silver badges108 bronze badges

answered Feb 9, 2020 at 6:02

Michael Francis

8,90712 gold badges48 silver badges76 bronze badges

Sign up to request clarification or add additional context in comments.

Collectives™ on Stack Overflow

Java style enums in C++

1 Answer 1

Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

Comments

Your Answer

Sign up or log in

Post as a guest

Related