[RESOLVED] Need help with PHP & maths functions

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:

---

0
83
174
276
388
512
650
801
969
1154
1358
1584
1833
2107
2411
2746
3115
3523
3973
4470
5018
5624
6291
7028
7842
8740
9730
10824
12031
13363
14834
16456
18247
20224
22406
24815
27473
30408
33648
37224
41171
45529
50339
55649
61512
67983
75127
83014
91721
101333
111945
123660
136594
150872
166636
184040
203254
224466
247886
273742
302288
333804
368599
407015
449428
496254
547953
605032
668051
737627
814445
899257
992895
1096278
1210421
1336443
1475581
1629200
1798808
1986068
2192818
2421087
2673114
2951373
3258594
3597792
3972294
4385776
4842295
5346332
5901831
6517253
7195629
7944614
8771558
9684577
10692629
11805606
13034431

---

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

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:

---

0
150
301
452
603
754
905
1132
1359
1586
1814
2042
2270
2498
2501
2505
2509
2513
2518
2523
2528
2608
2688
2769
2850
2931
3013
3095
3552
4009
4466
4924
5382
5840
6299
6833
7367
7901
8435
8970
9505
10040
10351
10662
10973
11284
11595
11907
12219
12606
12994
13382
13770
14158
14546
14935
15699
16463
17228
17993
18758
19523
20288
21129
21970
22811
23653
24495
25337
26179
26796
27414
28032
28650
29269
29888
30507
31201
31895
32590
33285
33980
34676
35372
36443
37514
38585
39657
40729
41801
42874
44022
45170
46318
47466
48615
49764

---

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

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.

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

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