//: C12:Reflex.cpp

// From Thinking in C++, 2nd Edition

// Available at http://www.BruceEckel.com

// (c) Bruce Eckel 1999

// Copyright notice in Copyright.txt

// Reflexivity in overloading



class Number {

  int i;

public:

  Number(int ii = 0) : i(ii) {}

  const Number

  operator+(const Number& n) const {

    return Number(i + n.i);

  }

  friend const Number

    operator-(const Number&, const Number&);

};



const Number

  operator-(const Number& n1,

            const Number& n2) {

    return Number(n1.i - n2.i);

}



int main() {

  Number a(47), b(11);

  a + b; // OK

  a + 1; // 2nd arg converted to Number

//! 1 + a; // Wrong! 1st arg not of type Number

  a - b; // OK

  a - 1; // 2nd arg converted to Number

  1 - a; // 1st arg converted to Number

} ///:~