View Compilation Error

0_0_39278841_29874.cpp
0_0_39278841_29874.cpp(17) : error C2819: “std::set<std::string,std::less<_Kty>,std::allocator<_Kty>>”类型没有重载成员“operator ->”
        with
        [
            _Kty=std::string
        ]
        是否改用“.”?
0_0_39278841_29874.cpp(17) : error C2232: “->std::_Tree<std::_Tset_traits<_Kty,_Pr,_Alloc,false>>::size”: 左操作数有“class”类型，使用“.”
        with
        [
            _Kty=std::string
,            _Pr=std::less<std::string>
,            _Alloc=std::allocator<std::string>
        ]