As all of us know, in c++ there are 3 ways of sending a value to a function:   by value like this:  void Example(int); by reference like this :  void Example(int&amp;); by const reference:  void Example(const int&amp;);   In first method, a copy of value will be used in function and so the value just can be read cant be wrote. In second method, parameter can be read and wrote , and in third, parameter will be used directly without any copy but cant be wrote. as third method occupy less memory (without taking any copy of parameter) why we usually use first method?  what is differences between them. Thanks.
Is it better in C++ to pass by value or pass by constant reference?  I am wondering which is better practice.  I realize that pass by constant reference should provide for better performance in the program because you are not making a copy of the variable.
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