Percentage Increase function PHP

dr1234

I have a database driven website with products, standard cost, and web cost, which I have calculated the web cost as a 40% increase on the standard cost. I am trying to find a way that I can choose my own percentage increase on a group of products so that I can input into a text box the required percentage increase and get it to apply to the products web costs displayed in the table. Any help would be greatly appreciated.

Ashley_Sheridan

Where do you want to make the change? Are you wanting to make it in the DB and change the existing cost, or add a field and insert the new cost. Do you want it to only show on the page and be calculated at the checkout?

As you're question is pretty vague, and you've not mentioned anything you've tried, it's hard to give you much help on this one.

sneakyimp

If your question is about what "percentage increase" means, a 40% increase would mean that the new price is 140% the old price.

$percent_to_increase = 40;
$new_price = $old_price * (1 + ($percent_to_increase/100));

dr1234

Sorry I have not made my prroblem very clear as I am relatively new to PHP, the problem is creating a function in which, from a text box input, I can change the web price by changing the percentage increase for a particular group of products. The basic markup is 40% ($row_Products['StandardCost'] *= 1.40) however I would like to create a function which will enable manual input of any percentage in order to change the web price.

Ashley_Sheridan

You're still not really explaining what it is you need specifically. It's a bit like saying you need directions to some place, but not saying if you're walking, driving or getting a bus.

To increase an amount by some arbitrary value, it's just basic math:

$increase = intval($_REQUEST['increase']; // this will be the &#37; you want to increase, i.e. 40
$price *= ($increase/100+1);

sneakyimp

What part of this whole process are you finding confusing? The form input? The function? A database?

dr1234

I am finding the function confusing as I need a function that will increase the current price of a group of products by any percentage that is input by the user into a text box.

So for example if I wanted to increase all product prices within product group 100 by 25%, I would type 25 into a text box and use a submit button, then this would increase each price by 25%

bradgrafelman

But you've already been given two coding examples of how to do exactly that.

So I guess the real question is... what about those coding examples don't you understand?

dr1234

I am not entirely sure where to place this code in order for it to function. This is my form where I would like to have this function.

<form id="form1" name="form1" method="post" action="">
<label>
<table border="0">
<tr>
<td width="250"> </td>
<td width="250"> </td>
<td width="250"> </td>
<td width="250"><label>Percentage Increase

    <input name="Increase" type="text" onkeypress="return isNumberKey(event)"  id="Increase" size="4" maxlength="3" /> [B]// Text box for user to input specified precentage[/B]  %

<input type="submit" name="IncreaseButton" id="IncreaseButton" value="Submit" /> // This is the submit button for the percentage increase that submits the new price to the table</label></td>

  <td width="183">td>
</tr>

</table>
</label>

</form>