您如何专门研究std :: greater

Question

have a

std::list<MyBaseClass*> objects;

how ( mean a syntax) would you specialize std::greater for the sort method of std::list

template<> class std::greater<MyBaseClass*> {
public:
     bool operator()(const MyBaseClass*& lhs, const MyBaseClass*& rhs) const
     {
         return lhs->get_index() > rhs->get_index();
     }

produces the error:

C2662: 'int MyBaseClass::get_index(void)' : cannot convert 'this' pointer from 'const MyBaseClass' to 'MyBaseClass &' Conversion loses qualifiers

can you explain me the problem please?

Answer 1

您的eidos::MyBaseClass::get_index()需要标记为“ const”。