i write c++ code it run perfectely with g++ compiler but same code when i compile with
GCC compiler it gives linker error , followed these linker error

/tmp/ccfZtXOQ.o(.text+0x22): In function `main':
conf_system.cpp: undefined reference to `operator new(unsigned int)'
/tmp/ccfZtXOQ.o(.text+0x79):conf_system.cpp: undefined reference to `operator delete(void*)'
/tmp/ccfZtXOQ.o(.text+0x97): In function `__tcf_0':
conf_system.cpp: undefined reference to `std::ios_base::Init::~Init()'
/tmp/ccfZtXOQ.o(.text+0xc4): In function `__static_initialization_and_destruction_0(int, int)':
conf_system.cpp: undefined reference to `std::ios_base::Init::Init()'
/tmp/ccfZtXOQ.o(.gnu.linkonce.t._ZN8sys_conf7displayEv[sys_conf::display()]+0x10): In function `sys_conf::display()':
conf_system.cpp: undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&)'
/tmp/ccfZtXOQ.o(.gnu.linkonce.t._ZN8sys_conf7displayEv[sys_conf::display()]+0x15):conf_system.cpp: undefined reference to `std::cout'
/tmp/ccfZtXOQ.o(.gnu.linkonce.t._ZN8sys_conf7displayEv[sys_conf::display()]+0x1a):conf_system.cpp: undefined reference to `std::basic_ostream<char, std::char_traits<char> >:perator<<(std::basic_ostream<char, std::char_traits<char> >& (*)(std::basic_ostream<char, std::char_traits<char> >&))'
/tmp/ccfZtXOQ.o(.gnu.linkonce.t._ZN8sys_conf7displayEv[sys_conf::display()]+0x27):conf_system.cpp: undefined reference to `std::basic_ostream<char, std::char_traits<char> >:perator<<(long)'
/tmp/ccfZtXOQ.o(.gnu.linkonce.t._ZN8sys_conf7displayEv[sys_conf::display()]+0x32):conf_system.cpp: undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::endl<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&)'
/tmp/ccfZtXOQ.o(.gnu.linkonce.t._ZN8sys_conf7displayEv[sys_conf::display()]+0x38):conf_system.cpp: undefined reference to `std::basic_ostream<char, std::char_traits<char> >:perator<<(std::basic_ostream<char, std::char_traits<char> >& (*)(std::basic_ostream<char, std::char_traits<char> >&))'
/tmp/ccfZtXOQ.o(.eh_frame+0x11): undefined reference to `__gxx_personality_v0'
collect2: ld returned 1 exit status

Can you show us the complete gcc command that you are passing ?

here that command
gcc conf_system.cpp -o conf_system

Hmmm.. try

vino
it works.........
thanks a lot,
i am new unix programming i can u suggest me any book for it

There are a whole lot of materials on the net. To start with you can browse the FAQ section of this forum Unix Tutorials/Programming Tutorials/Shell Scripting Tutorials