Compilare: user.cpp: In function ‘void read()’: user.cpp:7:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("subset2.in", "r", stdin); ^ user.cpp:8:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d", &n, &k); ^ user.cpp: In function ‘void write()’: user.cpp:27:40: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("subset2.out", "w", stdout); ^