/in/foo.cc: In function 'int main()':
/in/foo.cc:14:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int j=0;j<=s.size();j++)
               ~^~~~~~~~~~
/in/foo.cc:10:15: warning: unused variable 'x' [-Wunused-variable]
   int a,b,c,d,x;
               ^