Compilare: user.cpp: In function ‘int main()’: user.cpp:16:30: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("rest.in","r",stdin); ^ user.cpp:17:32: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("rest.out","w",stdout); ^ user.cpp: In function ‘void Next()’: user.cpp:81:46: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] std::fread(buf, 1, Lim, stdin), u = 0; ^