overloading the casting operator

[agauad]

Hi every one.

First of all I'll excuse me for the misspellings you'll find in the following text.

I'm trying to find out a way to encapsulate the primitive numeric types into a single interface so I will be able to define dependant classes such as Point, for saying, without explictly defining the numeric type and, at the same time, avoid using a Template class. So I tried to define within the abstract base class called Scalar (representing any scalar set) I defined the common operations by overloading the aritmetic, comparative and assignment operators. And finally I tried to overload the casting operator (as I think it is) called
Scalar::operator()(void) and declared it for every combination of numeric declaration (char,short int,int,long int,long long int, unsigned, and so on);
When I compiled it using MinGW the compiler throwed a error saying that every operator overload distinct that the one declared as int Scalar::operator()(void) was overriding this declaration.

class Scalar{
public:
  Scalar();

  Scalar(const Scalar&);

  /** aritmetic, comparative and assignment operators **/

  // here the compilers says that i'm overriding the int operator()(void);
  char operator()(void) = 0; 

  // this one throws no errors
  int operator() (void) = 0;

  // same error as in char
  unsigned int operator()(void) = 0;

  // same error as in char
  long double operator()(void) = 0;

 /** and so on... */


}

I've derived the class Integer from this one for testing and well as it fails here it also fails there.
Does anyone have a clue on what's going on..
Thanks in advance
Looking forward for hearing any answer on this subject.

[R0mai]

You are overloading operator()() here.
It doesn't compile because overloaded functions must have a different argument list : overloaded functions can't differ JUST in return type. But as I understand you want to overload the casting operator, which has a slightly different syntax:

class Scalar {
//...
operator char() = 0;
operator int() = 0;
operator double() = 0;
//...
};