c++ - How to solve error LNK2019 -

c++ - How to solve error LNK2019 -

i sending simple email in c++. downloaded sample c++ programme below link. http://cboard.cprogramming.com/cplusplus-programming/125655-sending-simple-email-cplusplus.html sample programme seems nail next error when compiling. please help me solution.

error 8 error lnk2019: unresolved external symbol _send_mail referenced in function _wmain error 9 error lnk2019: unresolved external symbol __imp__recv@16 referenced in function "int __cdecl connect_to_server(char const *)" (?connect_to_server@@yahpbd@z) error 10 error lnk2019: unresolved external symbol __imp__connect@12 referenced in function "int __cdecl connect_to_server(char const *)" (?connect_to_server@@yahpbd@z) error 11 error lnk2019: unresolved external symbol __imp__htons@4 referenced in function "int __cdecl connect_to_server(char const *)" (?connect_to_server@@yahpbd@z) error 12 error lnk2019: unresolved external symbol __imp__socket@12 referenced in function "int __cdecl connect_to_server(char const *)" (?connect_to_server@@yahpbd@z) error 13 error lnk2019: unresolved external symbol __imp__getprotobyname@4 referenced in function "int __cdecl connect_to_server(char const *)" (?connect_to_server@@yahpbd@z) error 14 error lnk2019: unresolved external symbol __imp__gethostbyname@4 referenced in function "int __cdecl connect_to_server(char const *)" (?connect_to_server@@yahpbd@z)

probably have declared function in class, forgotten utilize scope resolution operator in definition. atleast that's gave me error.

c++ linker unresolved-external lnk2019