View Compilation Error

0_0_2211767_13800.cpp
0_0_2211767_13800.cpp(14) : error C2079: “in”使用未定义的 class“std::basic_ifstream<_Elem,_Traits>”
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        0_0_2211767_13800.cpp(14) : 参见对正在编译的类模板实例化“std::basic_ifstream<_Elem,_Traits>”的引用
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
        0_0_2211767_13800.cpp(14) : 参见对正在编译的类模板实例化“std::basic_ifstream<_Elem,_Traits>”的引用
        with
        [
            _Elem=char,
            _Traits=std::char_traits<char>
        ]
0_0_2211767_13800.cpp(15) : error C2228: “.open”的左侧必须有类/结构/联合类型
        类型是“int”