Am I just bad at math, or is my calculator wrong?

[3raser]

Website: http://novacms.vacau.com/index.php

 

I'm trying to make a calculator for this game I play, it's fully developed, but with one bug. It doesn't do the math right.

 

$goal = The amount of EXP (Experience Points) someone wants to get

$exp = The amount of EXP they currently have

$npcs_exp["exp"] = The amount of EXP the monster has

 

But, when they enter in the information, the calculation is all screwed up. When I do it, it seems to give me the same number EACH time.

 

The part where the calculation "goes down". Remember, I'm trying to see how many times you need to kill a NPC to achieve your goal.

 

	//math
	$npc_exp_extract = mysql_query("SELECT exp FROM npcs WHERE name='$npc'");
	$npcs_exp = mysql_fetch_assoc($npc_exp_extract);

	$amount = $goal / $npcs_exp["exp"];

 

Full code:

 

<?php
$exp = $_POST["exp"];
$npc = $_POST["npc"];
$goal = $_POST["goal"];

mysql_connect("removed", "removed", "removed");
mysql_select_db("a2248602_npcs");

if(!$goal || !$npc || !$exp)
	{
		echo "<center><form action='index.php' method='POST'>GOAL: <input type='text' name='goal'> Current XP: <input type='text' name='exp'>";
		echo "NPC: <select name='npc'>";

		$npc_extract = mysql_query("SELECT * FROM npcs");
		while($npcs = mysql_fetch_assoc($npc_extract))
		{
		 echo "<option name='". $npcs['name'] ."'>". $npcs['name'] ."</option>";
		}

		echo "</select> <input type='submit'></form></center>";
	}
	else
	{
	//math
	$npc_exp_extract = mysql_query("SELECT exp FROM npcs WHERE name='$npc'");
	$npcs_exp = mysql_fetch_assoc($npc_exp_extract);

	$amount = $goal / $npcs_exp["exp"];

		if($amount=="1")
			{
				echo "You will need to kill a <b/>". $npc ."</b> <b>". $amount ."</b> more time. You earn ". $npcs_exp["exp"] ." XP for each kill from this NPC. | <a href='index.php'>Do another</a><br/><br/>";
			}
			else
			{
				echo "You will need to kill a <b/>". $npc ."</b> <b>". $amount ."</b> more times. You earn ". $npcs_exp["exp"] ." XP for each kill from this NPC. | <a href='index.php'>Do another</a><br/><br/>";
			}
	}

echo "<center>Made by Zaros from <a href='creation-x.net'>Creation-X</a></center>";
?>

 

Mod edit: DB credentials removed.

[BlueSkyIS]

echo out values and see if they are what you expect. the only other alternative is for us to go through your code, follow the logic and do the math. if you echo the values, php does that for you.

[Pikachu2000]

Unless I'm missing something, it looks like you execute the same query against the database each time without updating/incrementing/decrementing any of the variables or database values, so it's no surprise that the result is the same.

 

Also, off topic, but I noticed one thing that could be streamlined a bit.

$amount = $goal / $npcs_exp["exp"];

if($amount=="1") {
     echo "You will need to kill a <b/>". $npc ."</b> <b>". $amount ."</b> more time. You earn ". $npcs_exp["exp"] ." XP for each kill from this NPC. | <a href='index.php'>Do another</a><br/><br/>";
} else {
     echo "You will need to kill a <b/>". $npc ."</b> <b>". $amount ."</b> more times. You earn ". $npcs_exp["exp"] ." XP for each kill from this NPC. | <a href='index.php'>Do another</a><br/><br/>
}

 

Can be rewritten as

$amount = $goal / $npcs_exp["exp"];

echo "You will need to kill a <b/>". $npc ."</b> <b>". $amount ."</b> more time";
echo $amount == 1 ? '.' : 's.';
echo " You earn ". $npcs_exp["exp"] ." XP for each kill from this NPC. | <a href='index.php'>Do another</a><br/><br/>";

[3raser]

Unless I'm missing something, it looks like you execute the same query against the database each time without updating/incrementing/decrementing any of the variables or database values, so it's no surprise that the result is the same.

 

Also, off topic, but I noticed one thing that could be streamlined a bit.

$amount = $goal / $npcs_exp["exp"];

if($amount=="1") {
     echo "You will need to kill a <b/>". $npc ."</b> <b>". $amount ."</b> more time. You earn ". $npcs_exp["exp"] ." XP for each kill from this NPC. | <a href='index.php'>Do another</a><br/><br/>";
} else {
     echo "You will need to kill a <b/>". $npc ."</b> <b>". $amount ."</b> more times. You earn ". $npcs_exp["exp"] ." XP for each kill from this NPC. | <a href='index.php'>Do another</a><br/><br/>
}

 

Can be rewritten as

$amount = $goal / $npcs_exp["exp"];

echo "You will need to kill a <b/>". $npc ."</b> <b>". $amount ."</b> more time";
echo $amount == 1 ? '.' : 's.';
echo " You earn ". $npcs_exp["exp"] ." XP for each kill from this NPC. | <a href='index.php'>Do another</a><br/><br/>";

 

But there is no reason to do that, I believe. People just go to the calculator, type in the information, and it's suppose to do the math. They don't actually submit information into the database.

[Pikachu2000]

OK, I did miss something then, LOL. I'll have another look at it.

[ignace]

OK, I did miss something then, LOL. I'll have another look at it.

 

No you are correct!

 

You will need to kill a Black Demon 0.0149175240895 more times. You earn 306150 XP for each kill from this NPC.

 

The number 306150 remains constant because you don't subtract anything from it. And how do you kill a Black Demon 0.0149175240895 or 0.403253307202 times?

[Pikachu2000]

In that case, if the numbers are really that close, the ceil() function would be helpful when echoing how many more kills are needed.

[3raser]

OK, I did miss something then, LOL. I'll have another look at it.

 

No you are correct!

 

You will need to kill a Black Demon 0.0149175240895 more times. You earn 306150 XP for each kill from this NPC.

 

The number 306150 remains constant because you don't subtract anything from it. And how do you kill a Black Demon 0.0149175240895 or 0.403253307202 times?

 

You don't need to subtract anything from it. 306150, the amount of the Black Demon, needs to divide into their goal to see how manys time they need to kill it. When it does that, it gives me a number, but even if I change the amount of the goal, it stays the same.

[Pikachu2000]

Changing the GOAL field changes the result. Changing the XP field has no effect because the value of $_POST['exp'] isn't used anywhere in the calculation

[3raser]

Changing the GOAL field changes the result. Changing the XP field has no effect because the value of $_POST['exp'] isn't used anywhere in the calculation

 

Thank you! Fixed it.

[ignace]

And how do you kill a Black Demon 0.0149175240895 or 0.403253307202 times?

 

Did you also fix the above?