There are a few things wrong here: mainly to do with C# being case sensitive: "classA" is not the same as "ClassA", so you can't access the
const
value without getting the class name right:
ClassA classaa = new ClassA();
Console.WriteLine(ClassA.aaa);
Because it is a
const
value, it is implicitly static - so you can't access it via a class instance, only via the class name. So the instance you declare is unnecessary, as this won't work either:
ClassA classaa = new ClassA();
Console.WriteLine(classaa.aaa);