Compilare: user.c: In function ‘upper_bound’: user.c:37:5: warning: useless type name in empty declaration [enabled by default] int ; ^ user.c: In function ‘main’: user.c:51:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("proc2.in","r",stdin); ^ user.c:52:12: warning: ignoring return value of ‘freopen’, declared with attribute warn_unused_result [-Wunused-result] freopen("proc2.out","w",stdout); ^ user.c:53:10: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d%d%d",&n,&m,&st,&dr); ^ user.c:60:14: warning: ignoring return value of ‘scanf’, declared with attribute warn_unused_result [-Wunused-result] scanf("%d%d",&st,&dr); ^