Compilare: user.cpp: In function ‘void Insert(Trie*, char*)’: user.cpp:20:13: warning: NULL used in arithmetic [-Wpointer-arith] if (*s==NULL) {T->NrApp++; return;} ^ user.cpp: In function ‘void Remove(Trie*, char*)’: user.cpp:31:13: warning: NULL used in arithmetic [-Wpointer-arith] if (*s==NULL) {T->NrApp--;return;} ^ user.cpp: In function ‘int Find(Trie*, char*)’: user.cpp:43:13: warning: NULL used in arithmetic [-Wpointer-arith] if (*s==NULL) return T->NrApp; ^ user.cpp: In function ‘int Prefix(Trie*, char*, int)’: user.cpp:49:13: warning: NULL used in arithmetic [-Wpointer-arith] if (*s==NULL || T->fii[s[0]-'a']==NULL) return i; ^ user.cpp: In function ‘int main()’: user.cpp:63:17: warning: NULL used in arithmetic [-Wpointer-arith] if (*s==NULL) continue; ^ user.cpp: In function ‘int Find(Trie*, char*)’: user.cpp:45:1: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:54:35: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trie.in", "r", stdin); ^ user.cpp:55:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("trie.out", "w", stdout); ^ user.cpp:61:30: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%c", &x, &c); ^ user.cpp:62:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ /tmp/ccCSvzUO.o: In function `main': user.cpp:(.text.startup+0xbf): warning: the `gets' function is dangerous and should not be used.