Some questions about bitwise operators

I read about bitwise operators today and they seem rather handy to me. I also noticed Apple uses them too, for example with UIViewAutoresizing .

In my app I need to keep track of the seven days of the week. Each day can be either enabled or disabled. I used to have seven BOOL 's, but now I'm trying to use a single integer for this:

enum {

    DaysMonday = 1 << 0,

    DaysTuesday = 1 << 1,

    DaysWednesday = 1 << 2,

    DaysThursday = 1 << 3,

    DaysFriday = 1 << 4,

    DaysSaturday = 1 << 5,

    DaysSunday = 1 << 6

};

typedef NSUInteger Days;

My question is, how can I enable/disable those values now? I know I can check a variable days for a specific day like this:

if (days & DaysThursday) {

    // thursday enabled

}

But how do I..

1. enable thursday?
   


2. disable thursday?
   


3. toggle thursday?
   


4. enable all?
   


5. disable all?
   

Thank you.

Source: Tips4all