Eroare de compilare: user.cpp: In function ‘int main()’: user.cpp:13:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i=1;i<=T;++i) ^ user.cpp:16:18: error: could not convert ‘s.std::basic_string<_CharT, _Traits, _Alloc>::operator=<char, std::char_traits<char>, std::allocator<char> >((*(const std::basic_string<char>*)(& s1)))’ from ‘std::basic_string<char>’ to ‘bool’ if(s = s1) ^