/in/foo.cc: In function 'int main()':
/in/foo.cc:9:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(i=0;i<s.length()&&i<si;i++) cout<<s[i];
          ~^~~~~~~~~~~
/in/foo.cc:10:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for(i=si+len;i<s.length();i++) cout<<s[i];
               ~^~~~~~~~~~~
/in/foo.cc:6:15: warning: unused variable 'j' [-Wunused-variable]
  int si,len,i,j;
               ^