Compilare: user.cpp: In function ‘int main()’: user.cpp:42:36: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("deque.in", "r", stdin); ^ user.cpp:43:38: warning: ignoring return value of ‘FILE* freopen(const char*, const char*, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] freopen("deque.out", "w", stdout); ^ user.cpp: In function ‘char next()’: user.cpp:12:69: warning: ignoring return value of ‘size_t fread(void*, size_t, size_t, FILE*)’, declared with attribute warn_unused_result [-Wunused-result] if(p == BUFFER_SIZE) fread(buffer, 1, BUFFER_SIZE, stdin), p = 0; ^