Compilare: user.cpp: In function ‘void ins(char*, Trie*)’: user.cpp:18:14: warning: NULL used in arithmetic [-Wpointer-arith] if(*s == NULL) ^ user.cpp: In function ‘int main()’: user.cpp:79:26: warning: format ‘%s’ expects argument of type ‘char*’, but argument 2 has type ‘char (*)[40]’ [-Wformat=] scanf("%s\n",&cuv); ^ user.cpp:74:33: 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:75:35: 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:78:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&op); ^ user.cpp:79:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%s\n",&cuv); ^