Compilare: user.cpp: In function ‘int main()’: user.cpp:78:34: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] { freopen("next.in", "r",stdin); ^ user.cpp:79:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("next.out", "w",stdout); ^ user.cpp:81:12: warning: ignoring return value of ‘char* gets(char*)’, declared with attribute warn_unused_result [-Wunused-result] gets(s); ^ user.cpp:82:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%lld", &k); ^ /tmp/ccpf7ArT.o: In function `main': user.cpp:(.text.startup+0x59): warning: the `gets' function is dangerous and should not be used.