How does copy constructor work?

Question

How does a copy constructor work in c++

Error 1 error C2064: term does not evaluate to a function taking 1 arguments c:\\users\\thuan\\dropbox\\homework\\css

Answer 1

You are defining the object as a variable and then you are using it like a function. You are trying to construct the object when it's already constructed

Try

IntSet object2(9);
IntSet object1(object2);