錯誤 1 error LNK2005: "public: int __thiscall Teacher::getAge(void)" (?getAge@Teacher@@QAEHXZ) 已經在 demo.obj 中定義 D:\C++程序\demo\demo\Teacher.obj demo?

錯誤 2 error LNK2005: "public: class std::basic_string<char,struct std::char_traits<char>,class std::allocator<char> > __thiscall Teacher::getGender(void)" (?getGender@Teacher@@QAE?AV?$basic_string@DU?$char_traits@D@std@@V?$allocator@D@2@@std@@XZ) 已經在 demo.obj 中定義 D:\C++程序\demo\demo\Teacher.obj demo