Compilare: user.cpp: In function ‘int main()’: user.cpp:13:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("cartonase.in","r",stdin); ^ user.cpp:14:41: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen ("cartonase.out","w",stdout); ^ user.cpp:17:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d\n",&t); ^ user.cpp:20:16: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(v); ^ /tmp/ccRSTWqj.o: In function `main': user.cpp:(.text.startup+0x76): warning: the `gets' function is dangerous and should not be used.