/in/foo.cc: In function 'int main()':
/in/foo.cc:10:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0; i<s.size(); i++)
               ~^~~~~~~~~
/in/foo.cc:12:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   if(s.find(t1)!=-1)
      ~~~~~~~~~~^~~~