Help with Basic Math Functions (3 in 1)

exponder

This is a little hard to explain. And I'm horrible at math. I'm creating an "Experince Calculator" for an online rpg game. The game has various skills you can train. In each skill, you have different things you can do, to gain 'exp points' to reach your next level. What I need to do is take the below formula, and just produce a calculation.

An example, To gain exp in cooking, you can cook lobsters. Each lobster gives you 100exp points. You need to gain 3919exp points to reach level 4.

Value1 = Current Amount of Experince Points
Value2 = Desired experince Points
Value3 = Desired item(to create, each item as a set value of exp. points) to reach desired exp points.

I need php to subtract value 2, from value 1, and then divide that result, by value 3.

The result would dispaly something simular to;

(val2) - (val1) / (val3) = "You need to cook 34 lobsters to reach level 4".

I know this is confusing, but I have no idea where to begin. Could anyone point me in the right direction to do a calculation like this? Can php do that calculation in one function?

Any help or comments will be a great help.

Thanks in advance.

devinemke

you didn't say how/where you are storing all this data but i assume it's in a database. anyway, pull out all the data in variables and do something like:

$points = 300;
$points_per_lobster = 100;
$point_for_level_4 = 3919;

$points_needed = $point_for_level_4 - $points;
$lobsters_needed = $points_needed / $points_per_lobster;

echo '
you current have ' . $points . ' points<br>
the number of points need for level for is ' . $point_for_level_4  . '<br>
each lobster is worth ' . $points_per_lobster . ' points...so...<br><br>
you need ' . $points_needed . ' points which is ' . $lobsters_needed . ' lobsters to reach level 4<br><br>
since ' . $lobsters_needed . ' is not a nice round number you will actually have to cook ' . ceil($lobsters_needed) . ' lobsters
';

exponder

Acutally, all the data will come from the site-Visitors end.

There will be Input feilds that the user will fill out themself.

Value1 (Input text form) - User will fill this out themself.
Value 2 (Input Text form) & (Pulldown Menu - with level exp values inside, which will auto fill the form with the corrent exp points for that level)
Value 3 (Input Text Form) & (Pulldown menu - This will contain Various likes, such as lobsters with a preset value to them, like 100)

Then, hit calculate and the php file will do the math for them, telling them how many lobsters they'll need to reach the level which equals to Value2.

I hope this will explain it better.

devinemke

Originally posted by exponder
Acutally, all the data will come from the site-Visitors end.
There will be Input feilds that the user will fill out themself.

regardless, the math is still the same as my previous post.

exponder

Thank you greatly, Devin. I'm more than sure this will work perfectly.

exponder

The Calculator turned out to work great! 🙂
Demo; http://www.liquidclock.net/calculator_demo.html

Many thanks for the help. I have one more question and I'll leave you guys alone.

On the demo, you see the second part of the form. Where the user selects an item he wants to train to gain his or her desired level. Now the calculate.php takes this post data as a number. How can I reverse the data, back into the name?

The calculation on the next page is kinda cheesy, it displays as "You need to cook (number) of the item you selected ". Instead of "of the item you selected" how can I make it display what the user actually selected? We'll use Shrimp as an example.

"You need to cook 27 shrimp to reach the desired experience points." Here's my coding below.

<form name="calc" action="calculate.php" method="post" onSubmit="return Validate(this)">
Your Exact Experience:</td>
<td align="left" valign="middle" bgcolor="#E9EDD7">
<input type="text" name="current_exp" size="20"></td></tR>
<tr>
<td align="left" valign="middle" bgcolor="#E9EDD7">
Train Cooking With:</td>
<td align="left" valign="middle" bgcolor="#E9EDD7">
<select name="item" onChange="location=document.calc.item.options[document.calc.item.selectedIndex].value;" value="GO">
<option value="javascript:clear();">Select Item</option>
<option value="javascript:cooking(30);">Shrimp</option>
</select>&nbsp;<input type="text" name="item_" size="7" readonly>.exp per unit
</td></tr>
<tr>
<td align="left" valign="middle" bgcolor="#E9EDD7">
Desired Level:</td>
<td align="left" valign="middle" bgcolor="#E9EDD7">
<select name="level" onChange="location=document.calc.level.options[document.calc.level.selectedIndex].value;" value="GO">
<option value="javascript:clear2();">Select level</option>
<option value="javascript:level(0);">Level 1</option>
<option value="javascript:level(83);">Level 2</option>
</select><input type="text" name="level_" size="8" readonly> total experience.<br>
<input type="submit" value="Do Calculation">&nbsp; - &nbsp;<input type="reset" value="Clear Feilds">


// calculate.php
<?php

//  Post Data
$level_ = $level_; // Level Select
$current_exp = $current_exp; // User inputs his current XP level. 
$item_ = $item_; // User selects item to do/train


// First minus current exp by Desired level
$exp_needed = $level_ - $current_exp; 
// Then devide item_select by exp per item
$item_action = $exp_needed / $item_; 

// Display the results, and round off
echo ' You need to cook ' . ceil($item_action) . ' of the item you selected';

?>