Compilare: user.cpp: In function ‘char get_ch()’: user.cpp:14:42: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] fread(buf_in, 1, buf_size, stdin); ^ user.cpp: In function ‘int main()’: user.cpp:113:37: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("domino.in", "r", stdin); ^ user.cpp:114:39: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("domino.out", "w", stdout); ^ user.cpp:151:17: warning: ‘x’ may be used uninitialized in this function [-Wmaybe-uninitialized] euler(start); ^