Compilare: user.cpp: In member function ‘void Trie::add(int, char*, unsigned int)’: user.cpp:33:21: warning: NULL used in arithmetic [-Wpointer-arith] if (s[p] == NULL) { ^~~~ user.cpp: In function ‘void bfs(Trie*)’: user.cpp:54:14: warning: variable ‘leaf’ set but not used [-Wunused-but-set-variable] bool leaf = true; ^~~~ user.cpp: In function ‘int main()’: user.cpp:124:5: warning: ‘char* gets(char*)’ is deprecated [-Wdeprecated-declarations] gets(text); ^~~~ In file included from /usr/include/c++/6/cstdio:42:0, from /usr/include/x86_64-linux-gnu/c++/6/32/bits/stdc++.h:46, from user.cpp:1: /usr/include/stdio.h:638:14: note: declared here extern char *gets (char *__s) __wur __attribute_deprecated__; ^~~~ user.cpp:124:14: warning: ‘char* gets(char*)’ is deprecated [-Wdeprecated-declarations] gets(text); ^ In file included from /usr/include/c++/6/cstdio:42:0, from /usr/include/x86_64-linux-gnu/c++/6/32/bits/stdc++.h:46, from user.cpp:1: /usr/include/stdio.h:638:14: note: declared here extern char *gets (char *__s) __wur __attribute_deprecated__; ^~~~ user.cpp:127:9: warning: ‘char* gets(char*)’ is deprecated [-Wdeprecated-declarations] gets(s); ^~~~ In file included from /usr/include/c++/6/cstdio:42:0, from /usr/include/x86_64-linux-gnu/c++/6/32/bits/stdc++.h:46, from user.cpp:1: /usr/include/stdio.h:638:14: note: declared here extern char *gets (char *__s) __wur __attribute_deprecated__; ^~~~ user.cpp:127:15: warning: ‘char* gets(char*)’ is deprecated [-Wdeprecated-declarations] gets(s); ^ In file included from /usr/include/c++/6/cstdio:42:0, from /usr/include/x86_64-linux-gnu/c++/6/32/bits/stdc++.h:46, from user.cpp:1: /usr/include/stdio.h:638:14: note: declared here extern char *gets (char *__s) __wur __attribute_deprecated__; ^~~~ user.cpp: In function ‘void init()’: user.cpp:102:42: 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); ^ user.cpp:103:44: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result]