/in/foo.cc: In function 'int main()':
/in/foo.cc:46:14: warning: ISO C++ forbids converting a string constant to 'char*' [-Wwrite-strings]
  char * op = "+-*/()#";
              ^~~~~~~~~
/in/foo.cc:58:7: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(a==string::npos) break;
      ~^~~~~~~~
/in/foo.cc: In function 'int Judge(char, char)':
/in/foo.cc:22:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^