map with const keys but non const values?

Question

I have a situation, where I would like to have a map that does not allow to add/remove keys after initialization, but the values are allowed to change (thus I cannot simply

Answer 1

Could you create a wrapper that contains the value that allows the value to be mutated when const and put that in the map instead? Something like:

template
class Mutable {
    mutable T value;
public:
  const Mutable& operator=(const T& v) const { value = v; return *this; }
  T& get() const { return value; }  
};

Then your map can be of type

const std::map>

Live demo.