列计算中第一行为零

Question

I have a sketch of calculation like this

+------------+---------------+-------------+-------------+ 
    Name          IN              OUT          SALDO
+------------+---------------+-------------+-------------+ 
   Cash 8%        $50              -            $50
   Cash 4%        $20              -            $70
   Cash 12%       $70              -            $140
   Claimed         -              $60           $80
   Claimed         -              $20           $60
+------------------------------------------+-------------+ 
               TOTAL SALDO                      $60
+------------------------------------------+-------------+ 

The table above is what I am expecting to have. However this is the result what I got for now:

+------------+---------------+-------------+-------------+ 
    Name          IN              OUT          SALDO
+------------+---------------+-------------+-------------+ 
   Cash 8%        $50              -            0
   Cash 4%        $20              -            $50
   Cash 12%       $70              -            $70
   Claimed         -              $60           $140
   Claimed         -              $20           $80
+------------------------------------------+-------------+ 
               TOTAL SALDO                      $60
+------------------------------------------+-------------+ 

The problem is it give the 0 saldo in the first row even though the calculation is correct.

Here is my full code

    if ($saldo->num_rows > 0) {

        while($objek = $saldo->fetch_object()) {
            $i++;
            if ($objek->eight_percent) 
            {
            $sourceCash = $totalTwelve + $totalEight + $totalFour + $totalTwo - $totalClaim - $totalCashout;
            $totalEight = $totalEight + $objek->eight_percent;
                echo "<tr>
                        <td>Cashback 8%</td>
                        <td> - </td>
                        <td>".$sourceCash."</td>
                     </tr>";
            }

Thanks in advance for the help.

Answer 1

You're using a variable before you calculate its value.

For example, lets look at these two lines:

$sourceCash = $totalTwelve + $totalEight + $totalFour + $totalTwo - $totalClaim - $totalCashout;
$totalEight = $totalEight + $objek->eight_percent;

You're using the value of $totalEight to calculate $sourceCash, then you update the value of $totalEight. On the first iteration, the value of all of those columns will be zero, which is why you're displaying zero.

You probably meant to reverse the order of those two lines.