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

c++ constructor copy copy-constructor
Jony picture Jony · Apr 21, 2010 · Viewed 65.9k times · Source

Why must a copy constructor's parameter be passed by reference?

Answer

GManNickG picture GManNickG · Apr 21, 2010

Because if it's not by reference, it's by value. To do that you make a copy, and to do that you call the copy constructor. But to do that, we need to make a new value, so we call the copy constructor, and so on...

(You would have infinite recursion because "to make a copy, you need to make a copy".)

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