Compilare: user.cpp: In function ‘int main()’: user.cpp:10:34: 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:11:36: 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:15:27: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d %d\n",&n,&k); ^ user.cpp:17:28: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d\n",&a[i]); ^ user.cpp:27:18: warning: ‘s’ may be used uninitialized in this function [-Wmaybe-uninitialized] s=s+D.front(); ^