Compilare: user.cpp: In function ‘int main()’: user.cpp:46:31: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("queue.in","r",stdin); ^ user.cpp:47:33: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("queue.out","w",stdout); ^ user.cpp:48:18: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n",&n); ^ user.cpp:56:10: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(v); ^ /tmp/cccb2iJu.o: In function `main': user.cpp:(.text.startup+0xb7): warning: the `gets' function is dangerous and should not be used.