[RESOLVED] Need help with PHP & maths functions

**Jazz00006** · Dec 22nd, 2006, 11:45 PM

Well, I have this code,

PHP Code:


$a = 0; 

$goal2 = $goal - 1;

for ($x = 1;  $x <= $goal2; $x += 1) {

  $a = $a + intval($x + 300 * (2 ^ ($x / 7)));

  echo $a.'<BR>';

}

  $xp2 = intval($a / 4) - $xp;

echo $xp2;

and apart from the echos, it is completly wrong

Heres a sample: Clicky Me

and from 1 -> 99 the output should be this:

Code:

And for those who know VB6, this is the original function:

VB Code:

Public Function ExperienceNeededToGoalLevel(ByVal YourXP As Double, GoalLvl As Integer) As Double
   Dim a As Long
   Dim x As Long
   GoalLvl = GoalLvl - 1
   For x = 1 To GoalLvl
       a = a + Int(x + 300 * (2 ^ (x / 7)))
   Next
   ExperienceNeededToGoalLevel = Int(a / 4) - YourXP
End Function

I tried to modify it so it works with PHP, but the numbers are always off, is there something i am missing?

Cheers

**kows** · Dec 23rd, 2006, 02:22 AM

what are you entering into the function to get the sample output you gave?

I remade the function in PHP was entering 0 as experience and made a for() loop that looped through 1 to 99 to get the big list. you provided just about everything, except what you were entering as input to the function.. so without that, I'm not sure what else I can do. I rewrote the function though, this is what I made:

PHP Code:


<pre>

<?php

/*

Public Function ExperienceNeededToGoalLevel(ByVal YourXP As Double, GoalLvl As Integer) As Double

   Dim a As Long

   Dim x As Long

   GoalLvl = GoalLvl - 1

   For x = 1 To GoalLvl

       a = a + Int(x + 300 * (2 ^ (x / 7)))

   Next

   ExperienceNeededToGoalLevel = Int(a / 4) - YourXP

End Function

*/

  function getExperience($exp, $goal){

    $goal--;

    $e = 0;

    for($i = 1; $i < $goal; $i++){

      $e += ($i + 300) * (2^($i / 7));

    }

    return floor($e / 4) - $exp;

  }

  for($i = 1; $i < 99; $i++){

    echo getExperience(0, $i) . "\n";

  }

?>

</pre>

it outputs the following from the included for() loop:

Code:

provide a bit more information and I will try to help you out.

**kows** · Dec 23rd, 2006, 02:30 AM

I'm reinstalling VB right now so I can find out what your VB function outputs and so that I can mimic it.

edit: after tinkering for a bit, I couldn't figure out what was wrong. so.. I just typed this out in VB:

VB Code:

MsgBox (1 + 300 * 2 ^ (1 / 7))

It returned 332.2268. I typed the same equation in my calculator and got 332.2268. I typed the same equation into PHP, and got... 601. After breaking it down, it seems like PHP isn't handling the "^" operator correctly. I used the pow() function instead, and it worked perfectly. I've never worked with exponents before in PHP because I've never had the need to, but I guess you learn something new everyday. The function below does exactly what you want.

PHP Code:


<pre>

<?php

  function getExperience($exp, $goal){

    $goal--;

    for($i = 1; $i <= $goal; $i++){

      $e += intval($i + 300 * pow(2, $i / 7));

    }

    return intval($e / 4) - $exp;

  }

  for($i = 1; $i <= 99; $i++){

    echo $i . ". " . getExperience(0, $i) . "\n";

  }

?>

</pre>

The for() loop included will output the list you sampled in your first post.

edit again: had a problem with rounding, fixed it.

**penagate** · Dec 23rd, 2006, 05:52 AM

The ^ operator in C-based languages is XOR, not power.

**Jazz00006** · Dec 23rd, 2006, 07:13 AM

I did know that the ^ was wrong, and i did try the pow() function, but it still gave wrong awnsers, thanks kows for re-making it for me, it works perfectly

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