Copy constructor

Question

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Why should the copy constructor accept its parameter by reference in C++?

Why the argument to a copy constructor is passed by reference?

Answer 1

If it is passed by value it would require making a copy using a...COPY CONSTRUCTOR. :-)

Answer 2

You can't pass it by value because pass-by-value implies making/passing a copy of the thing ... making a copy of the parameter passed to the copyy constructor would be recursive, cause a stack overflow.

Answer 3

As others have mentioned you can't pass it by value - because then you'd need a copy to create a copy!

The only other alternative would be to pass by pointer, but the syntax would require address-of, like so:

MyClass copy(otherclass);  // by reference
MyClass copy(&otherclass); // by pointer