it is possible to change return type when override a virtual function in C++?

Question

I encounter a problems about override virtual functions, in fact,it is about hessian (a web service protocol).

it has a base class Object, and some derived classes :

Answer 1

No, you can't write toString in Object using a virtual 'value' function and override the return type. However you can write a virtual toString and with a template programming trick accomplish almost the same thing.

class Object
{
public:
  virtual std::string toString();
}


template < class ValueType >
class BasicType : Object
{
  public:
  typedef ValueType basic_type;
  basic_type value() { return value_; }

  std::string toString()
  {
    return some_convert_function( value_ );
  }

  private:
  basic_type value_;
}

typedef BasicType Long;
typedef BasicType       Int;