Compilare: user.cpp: In function ‘void insert(Trie*, char*)’: user.cpp:18:25: warning: NULL used in arithmetic [-Wpointer-arith] if (*s==NULL) ^ user.cpp: In function ‘void remove(Trie*, char*)’: user.cpp:32:25: warning: NULL used in arithmetic [-Wpointer-arith] if (*s==NULL) ^ user.cpp: In function ‘int NrAparitii(Trie*, char*)’: user.cpp:47:25: warning: NULL used in arithmetic [-Wpointer-arith] if (*s==NULL) ^ user.cpp: In function ‘int prefix(Trie*, char*, int)’: user.cpp:55:51: warning: NULL used in arithmetic [-Wpointer-arith] if (t->fii[s[0]-'a']==NULL || *s==NULL) ^ user.cpp: In function ‘int main()’: user.cpp:74:29: warning: NULL used in arithmetic [-Wpointer-arith] if (*s==NULL) continue; ^ user.cpp: In function ‘int NrAparitii(Trie*, char*)’: user.cpp:52:13: warning: control reaches end of non-void function [-Wreturn-type] } ^ user.cpp: In function ‘int main()’: user.cpp:67:45: 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:68:47: 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:72:40: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%c",&p,&z); ^ user.cpp:73:28: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ /tmp/ccDItyuy.o: In function `main': user.cpp:(.text.startup+0xd6): warning: the `gets' function is dangerous and should not be used.