Passing optional parameter by reference in c++

Question

I\'m having a problem with optional function parameter in C++

What I\'m trying to do is to write function with optional parameter which is passed by reference, so th

Answer 1

void foo(double &bar,
         double &foobar = const_cast(static_cast(0.0)))
{
   bar = 100;
   foobar = 150;
}