/in/foo.cc: In function 'int Atoint(std::__cxx11::string, int)':
/in/foo.cc:8:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<s.size();i++)
                  ^
/in/foo.cc: In function 'int main()':
/in/foo.cc:38:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (long long int i = 0; i < NUM_Str.length(); i++)
                                 ^
/in/foo.cc:60:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for (long long int i = 0; i < str1.length(); i++)
                                         ^
/in/foo.cc:69:41: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for (long long int i = 0; i < outstr.length(); i++)
                                         ^