YouTube like/dislike bar formula

[nathan.joshua]

Hello guys,

I've been working on a project recently and now my client wants a YouTube like/dislike bar

Anyway, I have been tampering with this like/dislike formula for a few hours now and it is starting to make me frustrated. This is what I have so far:

$likes and $dislikes sql query~

$a = $likes;
$b = $dislikes;
$c = $a/$b*100;

<div style="width:<?php echo $c; ?>%;"></div>

I am trying to echo out a percentage to display the dislike/like ratio using a divs width.

Unfortunately this code is not scalable and bugs under certain conditions i.e. if $b=>$a or $a==$b.

Does anyone have a solid formula I could learn from?

[JohnnyS]

i think the formula of getting the percentage should be:

$a = $likes;
$b = $dislikes;

$ap = ($a / ($a + $b)) * 100; // percentage if likes
$bp = ($b / ($a + $b)) * 100; // percentage if dislikes

[nathan.joshua]

You are some kind of mathematical sorcerer! Worked perfectly!


Full code below:

The PHP:

if($a > $b)
	{
	$c = ($a / ($a + $b)) * 100;
	}
if($b > $a)
	{
	$c = ($b / ($a + $b)) * 100;
	}
if($a == $b)
	{
	$c = 50;
	}

The HTML:

<div style="background-color:#000;width:200px;">
     <div style="background-color:#fff;height:30px;width:<?php echo $c; ?>%;"></div>
</div>

Thanks V7!

[countryqt30]

I think you would like to use "else", because the latter statements can't be true if one of the preceding was.

[nathan.joshua]

Originally Posted by countryqt30

I think you would like to use "else", because the latter statements can't be true if one of the preceding was.

As all the statements have unique queries and outputs there is little need for else. However, to create better syntax and readability, here are some elseif's added to the previous PHP:

if($a > $b)
	{
	$c = ($a / ($a + $b)) * 100;
	}
elseif($b > $a)
	{
	$c = ($b / ($a + $b)) * 100;
	}
elseif($a == $b)
	{
	$c = 50;
	}

[cbsmth]

Originally Posted by nathan.joshua

As all the statements have unique queries and outputs there is little need for else.

This is just nitpicking from my part, but there really is a difference: the three consecutive ifs will always be evaluated, whereas in the if/elseif variant, the interpreter will only proceed evaluating for as long as the preceding conditionals are false.

[adsonmycar]

Not sure if my comment would help a lot, but there are pre-made like dislike bar scripts online. They have been designed nicely and their license allows for commercial use too. For the same reason I don't calculate the 531 * 54, I just use a calculator.

[freeadstime]

This page may help: 9lessons.info/2010/07/youtube-like-rating-jquery-and-ajax.html