Copy constructur or bitwise copy

[drnrusu]

Hi I have a little c++ code but i'm not sure who makes the initialization for cp1.
Here is the code(in borlandc++ 3.1):

class A{
int i;
public:A(int val){i=val;
                        }
          A(A&a){i=a.i;
                       }
};
void main()
{
A obj(1); A cp1(obj); A cp2=obj;
}
 

The question is how makes the initialization for cp1. and for cp2;
I belive that the initialization are made by de copy construct, but someone told me that the bitewise copy makes them. Please help me because I'm confused;

[Ganon11]

When you have

A cp1(obj)

you are using the copy constructor.

When you have

A cp2 = obj;

you are using the assignment operator. Since you have not overloaded the assignment operator, the computer makes a bitwise copy of obj to cp2.

[weaknessforcats]

When you have

Code: ( cpp )
A cp2 = obj;

you are using the assignment operator.

Not true. You are still using the copy constructor.

The object cp2 is being created. Assignment only occurs after the object is created:

cp2 = obj;                 //assignment operator.
 

Further, C++ does not use bitwise copy. It uses memberwise copy. The compiler's default copy constructor calls the copy constructor on each member of the class. You only need to write your own copy constructor when this won't work for your class. Typically, these will be youer classes that have pointer members.