Compilare: user.cpp: In function ‘void add(char*)’: user.cpp:18:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<strlen(word); ++i) { ^ user.cpp:20:22: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (p->next[c] == NULL) ^ user.cpp:21:22: warning: array subscript has type ‘char’ [-Wchar-subscripts] p->next[c] = new Node; ^ user.cpp:22:22: warning: array subscript has type ‘char’ [-Wchar-subscripts] p = p->next[c]; ^ user.cpp: In function ‘void rem(Node*, char*)’: user.cpp:30:18: warning: NULL used in arithmetic [-Wpointer-arith] if (*word == NULL) ^ user.cpp:34:22: warning: NULL used in arithmetic [-Wpointer-arith] if (*(word+1) == NULL) ^ user.cpp: In function ‘int app(char*)’: user.cpp:51:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<strlen(word); ++i) { ^ user.cpp:53:23: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (!p->next[c]) ^ user.cpp:55:22: warning: array subscript has type ‘char’ [-Wchar-subscripts] p = p->next[c]; ^ user.cpp: In function ‘int prefix(char*)’: user.cpp:64:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int i=0; i<strlen(word); ++i) { ^ user.cpp:66:22: warning: array subscript has type ‘char’ [-Wchar-subscripts] if (p->next[c] == NULL) ^ user.cpp:68:22: warning: array subscript has type ‘char’ [-Wchar-subscripts] p = p->next[c]; ^ user.cpp: In function ‘int main()’: user.cpp:75:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trie.in", "rt", stdin); ^ user.cpp:76:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trie.out", "wt", stdout); ^ user.cpp:80:37: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %s\n", &cmd, word); ^