Bit Pattern in JavaScript

Question

I would like to ask help whether am I doing the right thing or not. You see I am trying to test myself by displaying the bit pattern of a number in the most efficient way as possible. But I'm having trouble on how to display the pattern cause I'm still learning javascript. Here's my code.

<script>
    var bitPattern = function(given) {
        for(var i = 1 << 31; i > 0; i = i / 2){
            document.write((given & i) ? 1 : 0);
        }
    };

    var number = prompt("Enter a number to convert: ");

    bitPattern(number);
</script>

`for (var i = 31; i >= 0; i--) { bit = (given >> i) & 1 }` would probably be a lot more efficient. — Marc B, Jun 22 '15 at 14:53
[Alternatives to document.write](http://stackoverflow.com/questions/4537963/what-are-alternatives-to-document-write) — samgak, Jun 22 '15 at 14:55
Whatever about the most efficient way, this won't work because `<<` returns a negative number. You can use `(1 << 31) >>> 0`, see http://stackoverflow.com/a/1908655/1469259 — CupawnTae, Jun 22 '15 at 14:56
@nicael: `number.toString(2)` won't work, because `number` is a string. `(+number).toString(2)` will work. See http://jsfiddle.net/dnagc0o6/ — Rick Hitchcock, Jun 22 '15 at 15:10

drinovc · Accepted Answer · 2015-06-22T15:12:53.533

3

The best way to do this is:

var number = prompt("Enter a number to convert: ");
var bitPattern = parseInt(number).toString(2);

document.write(bitPattern);

edited Jun 22 '15 at 15:12

answered Jun 22 '15 at 14:54

drinovc

521
5
16

I tried using this but it would display the original number rather than the bit pattern – Kael Jun 22 '15 at 15:09
What about now? But I prefer console output over writing results into web page. – drinovc Jun 22 '15 at 15:13
The previous one actually worked. Just forgot to add a "+" to my variable. – Kael Jun 22 '15 at 15:20

Bit Pattern in JavaScript

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