Compilare: user.c: In function ‘main’: user.c:58:5: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("slidingwindow.in","r",stdin); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ user.c:59:5: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("slidingwindow.out","w",stdout); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ user.c:60:5: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&n,&d); ^~~~~~~~~~~~~~~~~~~ user.c:63:9: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d",&v[i]); ^~~~~~~~~~~~~~~~~