Compilare: user.c: In function ‘main’: user.c:5:9: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("sir23.in","r",stdin),freopen("sir23.out","w",stdout),scanf("%d",&n); ^ user.c:5:39: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("sir23.in","r",stdin),freopen("sir23.out","w",stdout),scanf("%d",&n); ^ user.c:5:69: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] freopen("sir23.in","r",stdin),freopen("sir23.out","w",stdout),scanf("%d",&n); ^