Possible Duplicate:
Operator overloading
What causes C++ compiler error: must have argument of class or enumerated type?
I am trying to play a little bit with operator overloading and genericity in C++ and I seem to have 3 little errors when I try to compile. Have a class named Grandeur with template D, and then I inherit 3 classes from this one, named Temps(time), Longueur(size), Vitesse(speed), and I am trying to overload the operators such as when I do Temps+Temps->Temps, Vitesse+Vitesse=Vitesse,Longueur+Longueur->Longueur, Longueur/Time->Vitess etc.
In order not to write 3 times the same functions for the operations of same type, I use templates to utilise the genericity. But I have an error when I try to compile. Here is my code:
typedef double Longueur;
typedef double Temps;
typedef double Vitesse;
template<typename D>
class Grandeur {
protected :
double val; const char* unite;
public :
Grandeur(double qqc) : val(qqc) {}
Grandeur(int qqc) : val(qqc) {}
Grandeur(long qqc) : val(qqc) {}
Grandeur(float qqc) : val(qqc) {}
inline friend D operator+ (const D a, const D b) {
return D (a.val + b.val);
}
inline friend D operator- (const D a, const D b) {
return D (a.val - b.val);
}
inline friend double operator* (const D a, const D b) {
return a.val * b.val;
}
inline friend double operator/ (const D a, const D b) {
return a.val / b.val;
}
inline friend D operator* (D a, const int b) {
return D (a.val * b);
}
inline friend D operator/ (const D a, const int b) {
return D (a.val / b);
}
inline friend ostream& operator<< (ostream& os, D d) {
return os << d.val << d.u;
}
class Temps : public Grandeur<Temps> {
public:
};
class Vitesse : public Grandeur<Vitesse> {
public:
};
class Longueur : public Grandeur<Longueur> {
public:
};
};
inline Longueur operator* (const Vitesse v, const Temps t) {
return Longueur(v.val * t.val);
}
inline Vitesse operator/ (const Longueur l, const Temps t) {
return Vitesse(l.val / t.val);
}
inline Temps operator/ (const Longueur l, const Vitesse v) {
return Temps(l.val / v.val);
}
When I try to compile it says:
g++ essai.cc
In file included from essai.cc:4:0:
grandeurs.h:70:58: error: ‘Longueur operator*(Vitesse, Temps)’ must have an argument of class or enumerated type
grandeurs.h:74:58: error: ‘Vitesse operator/(Longueur, Temps)’ must have an argument of class or enumerated type
grandeurs.h:78:58: error: ‘Temps operator/(Longueur, Vitesse)’ must have an argument of class or enumerated type
The lines 70, 74 and 78 are those with the last 3 functions (the inlines). What can I do?
