/in/foo.cc: In function 'int main()':
/in/foo.cc:15:12: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (i=0;i<strlen(s);i++)
           ~^~~~~~~~~~
/in/foo.cc:18:13: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (j=i;j<i+strlen(t);j++)
            ~^~~~~~~~~~~~
/in/foo.cc:23:14: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (k=i;k<i+strlen(t);k++)
             ~^~~~~~~~~~~~