/in/foo.cc: In function 'int main()':
/in/foo.cc:48:9: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  while(i<s.size())
        ~^~~~~~~~~
/in/foo.cc:51:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while(i<s.size()&&s[i]>='0'&&s[i]<='9')
           ~^~~~~~~~~
/in/foo.cc:57:33: warning: array subscript has type 'char' [-Wchar-subscripts]
      while(top_p>0&&outcode[s[i]]<incode[ops[top_p]])
                                 ^
/in/foo.cc:57:52: warning: array subscript has type 'char' [-Wchar-subscripts]
      while(top_p>0&&outcode[s[i]]<incode[ops[top_p]])
                                                    ^
/in/foo.cc:65:18: warning: array subscript has type 'char' [-Wchar-subscripts]
   if(outcode[s[i]]==incode[ops[top_p]])
                  ^
/in/foo.cc:65:38: warning: array subscript has type 'char' [-Wchar-subscripts]
   if(outcode[s[i]]==incode[ops[top_p]])
                                      ^
/in/foo.cc: In function 'long long int op(long long int, long long int, char)':
/in/foo.cc:36:1: warning: control reaches end of non-void function [-Wreturn-type]
 }
 ^