Compilare: user.c: In function ‘A’: user.c:15:21: warning: assignment makes pointer from integer without a cast [enabled by default] s->f[*l-'a']=1,s->n++; ^ user.c: In function ‘main’: user.c:38:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("trie.in","r",stdin),freopen("trie.out","w",stdout); ^ user.c:38:38: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("trie.in","r",stdin),freopen("trie.out","w",stdout); ^ user.c:41:14: warning: ignoring return value of ‘fgets’, declared with attribute warn_unused_result [-Wunused-result] fgets(l,50,stdin); ^