Compilare: user.cpp: In function ‘int main()’: user.cpp:57:29: 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:58:31: 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:59:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ",&n); root=new trie; ^ user.cpp:61:13: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(ss); s[i]=ss; ^ user.cpp:64:16: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d ",&m); ^ user.cpp:66:15: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(ss+1); add_intrie(i); ^ /tmp/ccEDcM8R.o: In function `main': user.cpp:(.text.startup+0xd0): warning: the `gets' function is dangerous and should not be used.