Implementing dynamic typing in c++?

Question

Programming

Please tell me how to implement this?

class Variable
{
private:
    int type;
    union Value {
        char sign;
        int num;
    } value;
public:
    static const int SIGN = 1;
    static const int NUM = 2;
    Variable(char val)
    {
        type = SIGN;
        value.sign = val;
    }
    Variable(int val)
    {
        type = NUM;
        value.num = val;
    }

    Value get()
    {
        return value;
    }
};

That's what I threw, but I can't enter in any way, how can I return not a union, but specifically data? Or is this impossible?

Answer 1

You can overload type casting operators.

Answer 2

Look in the direction of boost::any and boost::variant, I can give an implementation very close to boost::any, but without boost.

Answer 3

You can on templates. But you do understand that union members are in the same place in memory and you cannot work with more than one at the same time, right?

template<typename T> Variable::get()
{
  return (T)value;
}

template<> Variable::get<int>()
{
  return value.num;
}

template<> Variable::get<char>()
{
  return value.sign;
}