Compilare: main.cpp: In function 'trie* Insert(trie*, char*)': main.cpp:33:12: warning: NULL used in arithmetic [-Wpointer-arith] if(*s==NULL) ^~~~ main.cpp: In function 'int main()': main.cpp:60:40: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("ahocorasick.in","r",stdin); ^ main.cpp:61:42: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result] freopen("ahocorasick.out","w",stdout); ^ main.cpp:63:20: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%s",str); ^ main.cpp:67:19: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); ^ main.cpp:71:22: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result] scanf("%s",s); ^