/in/foo.cc: In function 'int main()':
/in/foo.cc:11:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0;i<a.length();i++){
                 ~^~~~~~~~~~~
/in/foo.cc:12:13: warning: array subscript has type 'char' [-Wchar-subscripts]
   a1+=q[a[i]];
             ^
/in/foo.cc:14:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<b.length();i++){
              ~^~~~~~~~~~~
/in/foo.cc:15:13: warning: array subscript has type 'char' [-Wchar-subscripts]
   b1+=q[b[i]];
             ^