/in/foo.cc: In member function 'BigInt BigInt::operator+(const BigInt&) const':
/in/foo.cc:51:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 if (count == 0 && i >= s.size() && i >= b.s.size()) break;
                   ~~^~~~~~~~~~~
/in/foo.cc:51:38: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 if (count == 0 && i >= s.size() && i >= b.s.size()) break;
                                    ~~^~~~~~~~~~~~~
/in/foo.cc:53:7: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 if (i < s.size()) x += s[i];
     ~~^~~~~~~~~~
/in/foo.cc:54:7: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 if (i < b.s.size()) x += b.s[i];
     ~~^~~~~~~~~~~~
/in/foo.cc: In member function 'BigInt BigInt::operator*(int) const':
/in/foo.cc:66:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 if (carry == 0 && i >= s.size()) break;
                   ~~^~~~~~~~~~~
/in/foo.cc:68:7: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 if (i < s.size()) x += (long long)times * s[i];
     ~~^~~~~~~~~~
/in/foo.cc: In function 'std::ostream& operator<<(std::ostream&, const BigInt&)':
/in/foo.cc:81:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 for (int j = 0; j < strlen(buf); j++) out << buf[j];
                 ~~^~~~~~~~~~~~~
/in/foo.cc: In function 'bool check(std::__cxx11::string&, std::__cxx11::string&, int, int)':
/in/foo.cc:156:35: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 for (int i = 0, j = pos + blank;i < a.size() && j < b.size(); i++,j++)
                                 ~~^~~~~~~~~~
/in/foo.cc:156:51: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 for (int i = 0, j = pos + blank;i < a.size() && j < b.size(); i++,j++)
                                                 ~~^~~~~~~~~~
/in/foo.cc: In function 'bool check_through(std::__cxx11::string, std::__cxx11::string&, int)':
/in/foo.cc:164:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 for (;pos < b.size(); pos += a.size())
       ~~~~^~~~~~~~~~
/in/foo.cc: In function 'bool all(std::__cxx11::string&, char)':
/in/foo.cc:173:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 for (int i = 0; i < a.size(); i++)
                 ~~^~~~~~~~~~
/in/foo.cc: In function 'int main()':
/in/foo.cc:186:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 else for (int len = 1; len <= s.size(); len++)
                        ~~~~^~~~~~~~~~~