What does static_cast do to a T&?

Question

So I asked this question and I was tinkering around with solving it via static_cast. (Incidentally it does solve the problem, I\'m just not sure if I understand

Answer 1

Member function front returns a reference to the first element of a non-empty vector.

On the other hand standard algorithm replace declared like

template 
  void replace (ForwardIterator first, ForwardIterator last,
                const T& old_value, const T& new_value)

takes the third parameter also by reference. Thus in general the first element of the vector can be changed by the algorithm and as result processing of other elements of the vector by the algorithm can be incorrect.

Using static_cast a temporary object is created and will not be changed by the algorithm So the processing of all elements of the vector will be correct.

As for me then I suggested a C++ proposal to use keyword auto in such cases. For example

replace(begin(foo), end(foo), auto( foo.front() ), 13);