/in/foo.cc: In function 'int main()':
/in/foo.cc:9:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<=s1.size()-1;i++)if(s1[i]=='E')break;
               ~^~~~~~~~~~~~~
/in/foo.cc:14:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<=s.size()-1-1;i++){
              ~^~~~~~~~~~~~~~
/in/foo.cc:27:15: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(int i=0;i<=s.size()-1-1;i++){
              ~^~~~~~~~~~~~~~