Silly question

[nemok]

Hi,

Let's say I have this code:

#define ITEM1 0x00000001
#define ITEM2 0x00000002
#define ITEM3 0x00000003
int x=0;
x|=ITEM1;
x|=ITEM2;
x|=ITEM3;

I know I can check if an item is added by using "&", but how can I remove one item from the variable?

[googler]

This is not right first of all since when using bitmasks you should use non-overlapping bits.

#define ITEM1 0x00000001
#define ITEM2 0x00000002
#define ITEM3 0x00000004
int x=ITEM1 | ITEM2 | ITEM3;

but how can I remove one item from the variable?

Like this

x &= ~ITEM2;

[JMS]

I know I can check if an item is added by using "&",

#define ITEM1 0x00000001
#define ITEM2 0x00000002
#define ITEM3 0x00000004
int x=ITEM1 | ITEM2 | ITEM3;

if( x & ITEM1 )
{
   // Item is set
}
else
{
  // Item is not set
}

[Siddhartha]

I know I can check if an item is added by using "&", but how can I remove one item from the variable?

Using bitwise XOR (if the item exists).

Like this -

  if (x & ITEM1)
	x ^= ITEM1;