Compilare: user.cpp: In function ‘int main()’: user.cpp:54:29: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("seti.in","r",stdin); ^ user.cpp:55:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("seti.out","w",stdout); ^ user.cpp:56:15: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); gets(s); root=new trie; ^ user.cpp:56:24: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&n); gets(s); root=new trie; ^ user.cpp:58:15: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(ss+1); strcat(s+1,ss+1); ^ user.cpp:61:15: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&m); gets(s); ^ user.cpp:61:24: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&m); gets(s); ^ user.cpp:63:15: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(ss+1); add_intrie(i); ^ /tmp/ccmYq9JE.o: In function `main': user.cpp:(.text.startup+0x6a): warning: the `gets' function is dangerous and should not be used.