How does C# decide which enum value as a returned one? Any rules? [duplicate]

Question

I found a very intersting thing——Let's say:

 enum Myenum { a, b, c= 0 }
    public class Program
    {
        static void Main(string[] args)
        {
            Myenum ma = Myenum.a;
            Console.WriteLine(ma);
        }
    }

The result is a, why?

And if I say:

 enum Myenum { a, b=0, c}
    public class Program
    {
        static void Main(string[] args)
        {
            Myenum ma = Myenum.a;
            Console.WriteLine(ma);
        }
    }

The result becomes "b", why?

Answer 1

From Enum.ToString:

If multiple enumeration members have the same underlying value and you attempt to retrieve the string representation of an enumeration member's name based on its underlying value, your code should not make any assumptions about which name the method will return. For example, the following enumeration defines two members, Shade.Gray and Shade.Grey, that have the same underlying value.

Related: enum.ToString return wrong value?

So i would assign unique values if you wannt to rely on the name:

enum Myenum { hello = 1, world = 2, qiang = 3 }