unresolved external - Urgent help needed!!

[COTLG]

Please can someone help with this error:

Program1A.obj : error LNK2019: unresolved external symbol "class std::basic_ostream<char,struct std::char_traits<char> > & __cdecl operator<<(class std::basic_ostream<char,struct std::char_traits<char> > &,struct ErrorType const &)" (??6@YAAAV?$basic_ostream@DU?$char_traits@D@std@@@std@@AAV01@ABUErrorType@@@Z) referenced in function "void __cdecl TestRelationalOperators(class std::basic_ostream<char,struct std::char_traits<char> > &,struct ErrorType const &,struct ErrorType const &)" (?TestRelationalOperators@@YAXAAV?$basic_ostream@DU?$char_traits@D@std@@@std@@ABUErrorType@@1@Z)
Debug\Program1A.exe : fatal error LNK1120: 1 unresolved externals

I can paste all my program if needed.

Thanks.
Chike.

 

[uolj]

It cannot find the definition of the operator<< for the ErrorType struct. Have you defined that function?