c++ - Is Const important for Copy Constructor? -

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• why can non-const reference parameter bound temporary object? 2 answers

i'm running program on dev c++ , it's showing error of const.. in visual studio working fine. const important copy constructor?

#include<iostream> using namespace std;  class test {    /* class data members */ public:    test(test &t) { /* copy data members t*/}    test()        { /* initialize data members */ } };  test fun() {     cout << "fun() called\n";     test t;     return t; }  int main() {     test t1;     test t2 = fun();     return 0; } 

the copy constructor traditionally declared as

foo(const foo&); 

since assumed copy doesn't change object on right hand side (at least copier shouldn't change it, right?)

in standard c++, cannot bind temporary non-const reference. visual studio uses non-standard extension, , that's why code compiles, should not rely on non-standard extensions.

it not absolutely necessary have copy constructor taking rhs const reference, ok take reference. in case, won't able perform copy initialization rvalue (a temporary basically).