Bit count a variable

[Anon]

Do anyone know how I can count number of bits in a interger?

[vsego]

What do you mean: check how much memory it uses, or how "long" it is in binary (i.e. 1=>1, 2=>2, 31=>5, 32=>6,...)?

[Anon]

I wanted to count number of bits who are set to 1. Like this:

function bit_count($num) {
return strlen(str_replace('0','',decbin($num)));
}

[vsego]

Ok, that's fine. One thing: manual suggests use of ereg_replace:

function bit_count($num) {
return strlen(ereg_replace("0","",decbin($num)));
}