/in/foo.cc: In constructor 'Sig::Sig(std::vector<std::complex<double> >*)':
/in/foo.cc:58:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         while (m < V->size()) {
                ~~^~~~~~~~~~~
/in/foo.cc: In copy constructor 'Sig::Sig(const Sig&)':
/in/foo.cc:67:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < s.V->size(); ++i) {
                         ~~^~~~~~~~~~~~~
/in/foo.cc: In member function 'Sig Sig::fft() const':
/in/foo.cc:86:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < V->size(); ++i) {
                         ~~^~~~~~~~~~~
/in/foo.cc:92:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for (int k = 0; k < V->size(); k += m) {
                             ~~^~~~~~~~~~~
/in/foo.cc: In member function 'Sig Sig::ifft() const':
/in/foo.cc:114:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < V->size(); ++i) {
                         ~~^~~~~~~~~~~
/in/foo.cc: In copy constructor 'BigInteger::BigInteger(const BigInteger&)':
/in/foo.cc:192:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < s.T->size(); ++i) {
                         ~~^~~~~~~~~~~~~
/in/foo.cc: In member function 'BigInteger BigInteger::operator*(const BigInteger&)':
/in/foo.cc:214:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < T->size(); ++i) {
                         ~~^~~~~~~~~~~
/in/foo.cc:217:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < rhs.T->size(); ++i) {
                         ~~^~~~~~~~~~~~~~~
/in/foo.cc:229:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < lhs_out.V->size(); ++i) {
                         ~~^~~~~~~~~~~~~~~~~~~
/in/foo.cc:239:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < pro_out.V->size(); ++i) {
                         ~~^~~~~~~~~~~~~~~~~~~
/in/foo.cc: In member function 'void BigInteger::rearrange()':
/in/foo.cc:250:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < T->size() - 1; ++i) {
                         ~~^~~~~~~~~~~~~~~
/in/foo.cc: In member function 'void BigInteger::print()':
/in/foo.cc:267:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int i = 0; i < T->size(); ++i) {
                         ~~^~~~~~~~~~~
/in/foo.cc: In member function 'char* BigInteger::str()':
/in/foo.cc:277:37: warning: format '%d' expects argument of type 'int', but argument 3 has type '__gnu_cxx::__alloc_traits<std::allocator<long long int> >::value_type {aka long long int}' [-Wformat=]
         sprintf(s, "%d", (*T)[l - 1]);
                                     ^