Compilare: user.cpp: In function ‘int main()’: user.cpp:12:41: 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:13:43: 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:15:21: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d", &T); ^ user.cpp:17:25: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf ("%d", &n); ^ user.cpp:20:17: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets (s); ^ /tmp/ccOHWQqf.o: In function `main': user.cpp:(.text.startup+0x9a): warning: the `gets' function is dangerous and should not be used.