Question

I’ve got the following code:

print "\n1 & 11\n";
var_dump(1 & 11);

print "\n 2 & 222\n";
var_dump(2 & 222);

Why is the first result 1 ? And why is the second result 2?

The PHP Web site says that 2 & 222 (for example) should give me back a boolean value:

For example, $a & $b == true evaluates the equivalency then the bitwise and; while ($a & $b) == true evaluates the bitwise and then the equivalency.”

I don’t get it, how can 2 & 222 be 2 ?

Answer 1

In bits:

1. 01
2. 10
3. 11

The & operator returns all bits set to 1 in both numbers. So:

• 1 & 2 -> 01 & 10 -> 00 == 0
• 2 & 3 -> 10 & 11 -> 10 == 2