/in/foo.cc: In function 'int main()':
/in/foo.cc:19:12: warning: array subscript has type 'char' [-Wchar-subscripts]
   if(h[a[i]]==0)
            ^
/in/foo.cc:21:10: warning: array subscript has type 'char' [-Wchar-subscripts]
    h[a[i]]=b[i];
          ^
/in/foo.cc:24:12: warning: array subscript has type 'char' [-Wchar-subscripts]
   if(h[a[i]]!=0 && h[a[i]]!=b[i])
            ^
/in/foo.cc:24:26: warning: array subscript has type 'char' [-Wchar-subscripts]
   if(h[a[i]]!=0 && h[a[i]]!=b[i])
                          ^