单选题
有如下程序:
#include
using namespace std;
class Boat;
class Car{
public:
Car(int i):weight(i){ }
friend int Total(const Car &c.const Boat &b); //①
private:
int weight;
};
class Boat{
public:
Boat(int i):weight(i){ }
friend int Total(const Car &c,const Boat &b);
private:
int weight;
};
int Total(const Car &c,const Boat &b){ //②
return c.weight+b.weight;
}
int main(){
Car c(10);
Boat b(8);
cout<<"The total weight is"<