bitset AND operator question

[brakepad]

Copied this from the reference page
bitset<4> first (string("1001"));
bitset<4> second (string("0011"));

cout << (first^=second) << endl; // 1010 (XOR,assign)
cout << (first&=second) << endl; // 0010 (AND,assign)
cout << (first|=second) << endl; // 0011 (OR,assign)

1001 bitwise AND 0011 is 0001, isn't it?
also how come 1001 bitwise OR 0011 turn out to be 0011?

[PanGalactic]

your are doing:

1001 ^ 0011 = 1010
1010 & 0011 = 0010
0010 | 0011 = 0011

Note that you are doing operation= ... first is being continually changed.

[Disch]

also how come 1001 bitwise OR 0011 turn out to be 0011?

It's not. 1001 OR 0011 is 1011

Look at the code. Notice that you're using the assignment operators (^=, &=, |=). So each time you're modifying first.

cout << (first^=second) << endl; // 1001 XOR 0011 = 1010
// first now == 1010

cout << (first&=second) << endl; // 1010 AND 0011 = 0010
// first now == 0010

cout << (first|=second) << endl; // 0010 OR 0011 = 0011
// first now == 0011 

EDIT: doh, too slow