c++ - Why does "most important const" have to be const? -

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in http://herbsutter.com/2008/01/01/gotw-88-a-candidate-for-the-most-important-const/ mentions "most important const" c++ deliberately specifies binding temporary object reference const on stack lengthens lifetime of temporary lifetime of reference itself. wondering why c++ allows lifetime of object lengthened when reference const , not when isn't? rational behind feature , why have const?

here's example:

void square(int &x) {   x = x * x; }  int main() {   float f = 3.0f;    square(f);    std::cout << f << '\n'; }

if temporaries bind non-const lvalue references, above happily compile, produce rather surprising results (an output of 3 instead of 9).


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