/in/foo.cc: In function 'int main()':
/in/foo.cc:17:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
  for (i = 0; i < strlen(s); i++)
              ~~^~~~~~~~~~~
/in/foo.cc:20:17: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for (j = i; j < i + strlen(t1); j++)
               ~~^~~~~~~~~~~~~~~~
/in/foo.cc:24:18: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
    for (k = i; k < i + strlen(t1); k++)
                ~~^~~~~~~~~~~~~~~~
/in/foo.cc:16:12: warning: unused variable 'n' [-Wunused-variable]
  int i, j, n = 0, k = 0;
            ^