Consider the following ways of declaring and initializing a variable of type C:
C c1;
C c2;
c2 = C();
C c3(C());
C c4 = C();
Are all of these completely equivalent to each other, or can some of these differ depending on the exact definition of C? (assuming it has public default and copy constructors).
These mean:
C c1; // default constructor
C c2; // default constructor
c2 = C(); // default constructor followed by assignment
C c3(C()); // default constructor possibly followed by copy constructor
C c4 = C(); // default constructor possibly followed by copy constructor
Note the compiler can elide copy constructor calls. Are they equivalent? - well, it depends on what the copy constructor and assignment operator do.
c3 and c4 wouldn't compile, but c2 still would, right? (including the assignment). What about a call to func(c2) - would this also fail to compile with a private copy constructor?
C c3(C()); from function declaration. You may need add extra brackets to avoid compiler warning: C c3((C()));