/in/foo.cc: In function 'int main()':
/in/foo.cc:14:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for(int i=0;i<s.length();i++) tmp+=(int)(s[i]-'0');
                      ^
/in/foo.cc:55:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for(int i=0;i<s.length();i++){
                          ^
/in/foo.cc:62:20: warning: ignoring return value of 'int system(const char*)', declared with attribute warn_unused_result [-Wunused-result]
     system("pause");
                    ^