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

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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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  3. What does the explicit keyword mean?
  4. What is the copy-and-swap idiom?
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  7. Why do we not have a virtual constructor in C++?
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  11. Creating an instance of class
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  19. Has the new C++11 member initialization feature at declaration made initialization lists obsolete?
  20. In C++ can constructor and destructor be inline functions?
  21. What is a non-trivial constructor in C++?
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  25. C++: constructor initializer for arrays
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  36. How to copy a string of std::string type in C++?
  37. How many constructors does the class have?
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  40. What is the order of evaluation in a member initializer list?
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  42. Defining an object without calling its constructor in C++
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  44. call to pure virtual function from base class constructor
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  46. Do built-in types have default constructors?
  47. Why shared_from_this can’t be used in constructor from technical standpoint?
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