/in/foo.cc: In function 'int main()':
/in/foo.cc:20:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
             for(int i=0;i<strlen(a);i++)
                          ^
/in/foo.cc:33:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         if(sum==strlen(a))
               ^