我有一个主机类,它采用两个策略,sayhello
并且talk
. 该策略talk
是一个类模板,它本身采用例如sayhello
. 问题在于(我试图用 解决这个钻石问题)sayhello::saySomething
是模棱两可的。host2
virtual
我该如何解决这种歧义?还是一般来说有更好的设计来解决这些问题?
例子:
#include <iostream>
class sayhello {
protected:
void saySomething(void) {
std::cout<<"Hello!"<<std::endl;
}
};
template<typename T>
class talk : private T {
protected:
void doSomething(void) {
T::saySomething();
}
};
template<typename T>
class host1 : virtual T {
public:
void hostAction(void) {
T::doSomething();
}
};
template<typename T, typename L>
class host2 : private T, private L {
public:
void hostAction(void) {
T::doSomething();
L::saySomething();
}
};
int main() {
host1<talk<sayhello> > HOST1;
HOST1.hostAction(); // ok that works
host2<talk<sayhello>,sayhello> HOST2;
HOST2.hostAction(); // error, ambiguity!
return 0;
}