Compilare: user.cpp: In function ‘void adv()’: user.cpp:36:28: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf, 1, DIM, stdin); ^ user.cpp: In function ‘int main()’: user.cpp:85:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ograzi.in", "r", stdin); ^ user.cpp:86:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("ograzi.out", "w", stdout); ^ user.cpp:87:27: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf, 1, DIM, stdin); ^