请问这个链接错误是什么意思?
--------------------Configuration: password - Win32 Debug--------------------
Linking...
PasswordReminder.obj : error LNK2001: unresolved external symbol "public: class CString const & __thiscall CString::operator=(char const *)" (??4CString@@QAEABV0@PBD@Z)
PasswordReminder.obj : error LNK2001: unresolved external symbol "public: void __cdecl CString::Format(char const *,...)" (?Format@CString@@QAAXPBDZZ)
LIBCD.lib(crt0.obj) : error LNK2001: unresolved external symbol _main
Debug/password.exe : fatal error LNK1120: 3 unresolved externals
Error executing link.exe.
password.exe - 4 error(s), 0 warning(s)
不明白这个链接错误是怎么回事public: class CString const & __thiscall CString::operator=(char const *)" (??4CString@@QAEABV0@PBD@Z)
毛病出在哪里,应该如何修改呢?