Ho da poco installato Ubuntu 8.10 e volevo compilare alcuni programmi in c++, ma dopo aver installato il pacchetto mi da il seguente codice d'errore:

codice:
cat primo.cpp 
#include <iostream>

using namespace std;

int main(){
   int i,tmp,som=0;
   for(i=0;i<10;i++){
      cout << "inserire il " << i+1 << " numero ("<< som <<"): ";
      cin >> tmp;
      som += tmp;
      if(tmp==0) break;}
   cout << "la somma dei " << i << " numeri e': " << som << endl;
   return 0;
}
compiliamo:

codice:
 gcc -o primo primo.cpp 
/tmp/cczsiFCv.o: In function `__static_initialization_and_destruction_0(int, int)':
primo.cpp:(.text+0x1d): undefined reference to `std::ios_base::Init::Init()'
primo.cpp:(.text+0x22): undefined reference to `std::ios_base::Init::~Init()'
/tmp/cczsiFCv.o: In function `main':
primo.cpp:(.text+0x8f): undefined reference to `std::cout'
primo.cpp:(.text+0x94): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
primo.cpp:(.text+0xa0): undefined reference to `std::basic_ostream<char, std::char_traits<char> >::operator<<(int)'
primo.cpp:(.text+0xb0): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
primo.cpp:(.text+0xc1): undefined reference to `std::basic_ostream<char, std::char_traits<char> >::operator<<(int)'
primo.cpp:(.text+0xd1): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
primo.cpp:(.text+0xdf): undefined reference to `std::cin'
primo.cpp:(.text+0xe4): undefined reference to `std::basic_istream<char, std::char_traits<char> >::operator>>(int&)'
primo.cpp:(.text+0x10e): undefined reference to `std::cout'
primo.cpp:(.text+0x113): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
primo.cpp:(.text+0x124): undefined reference to `std::basic_ostream<char, std::char_traits<char> >::operator<<(int)'
primo.cpp:(.text+0x134): undefined reference to `std::basic_ostream<char, std::char_traits<char> >& std::operator<< <std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*)'
primo.cpp:(.text+0x145): undefined reference to `std::basic_ostream<char, std::char_traits<char> >::operator<<(int)'
primo.cpp:(.text+0x14d): 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> >&)'
primo.cpp:(.text+0x155): undefined reference to `std::basic_ostream<char, std::char_traits<char> >::operator<<(std::basic_ostream<char, std::char_traits<char> >& (*)(std::basic_ostream<char, std::char_traits<char> >&))'
/tmp/cczsiFCv.o:(.eh_frame+0x11): undefined reference to `__gxx_personality_v0'
collect2: ld returned 1 exit status
Dove è il problema?? sotto win lo compila..