hi all
i am getting the following error

Undefined first referenced
symbol in file
std::basic_ostream<char,std::char_traits<char> >&operator<<(std::basic_ostream<char,std::char_t ra
its<char> >&,const basic_string<char,char_traits_char,allocator<char> >&) OMConnectivity.o

OMConnectivity.o - is object file for my code..

do i hav to include any standard library??
i hav already included the following libraries .
#include <iostream.h>
#include <iomanip.h>
#include <ctype.h>
#include <fstream.h>
#include <signal.h>

do i have to furnish some more details regarding this ??
waiting for a solution
Sai koushal