Compilare: user.c: In function ‘main’: user.c:62:19: warning: format ‘%lu’ expects argument of type ‘long unsigned int’, but argument 3 has type ‘size_t {aka unsigned int}’ [-Wformat=] sprintf(obuf, "%lu\n", n); ^ user.c:64:29: warning: format ‘%lu’ expects argument of type ‘long unsigned int’, but argument 4 has type ‘size_t {aka unsigned int}’ [-Wformat=] bsz = sprintf(obuf, "%s%lu ", obuf, s[i]); ^ user.c:18:5: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("strmatch.in", "r", stdin); ^ user.c:19:5: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("strmatch.out", "w", stdout); ^ user.c:67:5: warning: ignoring return value of ‘write’, declared with attribute warn_unused_result [-Wunused-result] write(1, obuf, bsz); ^