Undefined variable when it is under isset

Question

Create a sum of multiple array, but it shows undefined variable

Total Box Charges: <?php if(isset($box_chrs)){echo $a = array_sum($box_chrs);}?><br>
Total Installation Charges: <?php if(isset($instl_chrs)){echo $b = array_sum($instl_chrs);}?><br>
Total Other Charges: <?php if(isset($other_chrs)){echo $c = array_sum($other_chrs);}?><br>
Total Package Charges:<?php if(isset($pkg_val)){echo $d = array_sum($pkg_val);}?><br>
Total Amount: <?php if(isset($total_amt)){echo $e = array_sum($total_amt);}?>
          <br>
Grand Total:
          <?php
          if(isset($a) || isset($b) || isset($c) || isset($d) || isset($e))
          {
            $sum = array($a, $b, $c, $d, $e);
            echo array_sum($sum);
          }
          ?>

I use isset but in the output it shows Notice: Undefined variable: a. It make sum of other, but when some variable is null, then it shows Undefined variable .when I set all the variable it shows perfect. If any variable is null, then it shows error.

So my question is How to sum of those variable?

It is a experimental script I am coding, and I am not in pro yet. :)

Thanks a lot.

Answer 1

Update

Your code is a bit complicated, I don't think it needs to be. When you want to get the total sum, add the parts where you know they exists - in the individual ifs.

<?php $sum = array(); ?>
Total Box Charges: <?php if(isset($box_chrs)){
    echo $a = array_sum($box_chrs);
    $sum[] = $a;
}?><br>
Total Installation Charges: <?php if(isset($instl_chrs)){
    echo $b = array_sum($instl_chrs);
    $sum[] = $b;
}?><br>
Total Other Charges: <?php if(isset($other_chrs)){
    echo $c = array_sum($other_chrs);
    $sum[] = $c;
}?><br>
Total Package Charges:<?php if(isset($pkg_val)){
    echo $d = array_sum($pkg_val);
    $sum[] = $d;
}?><br>
Total Amount: <?php if(isset($total_amt)){
    echo $e = array_sum($total_amt);
    $sum[] = $e;
}?>
          <br>
Grand Total:
<?php
echo array_sum($sum);
?>

This will add each part to the $sum if it is set. You cannot use one statement for all of these because you don't know which is set. You could do it like this as well, but I'd prefer the solution posted above ;)

Total Box Charges: <?php if(isset($box_chrs)){ echo $a = array_sum($box_chrs); }?><br>
Total Installation Charges: <?php if(isset($instl_chrs)){echo $b = array_sum($instl_chrs);}?><br>
Total Other Charges: <?php if(isset($other_chrs)){echo $c = array_sum($other_chrs);}?><br>
Total Package Charges:<?php if(isset($pkg_val)){echo $d = array_sum($pkg_val);}?><br>
Total Amount: <?php if(isset($total_amt)){echo $e = array_sum($total_amt);}?>
          <br>
Grand Total:
<?php
$sum = array();
if (isSet($a))
    $sum[] = $a;
if (isSet($b))
    $sum[] = $b;
if (isSet($c))
    $sum[] = $c;
if (isSet($d))
    $sum[] = $d;
if (isSet($e))
    $sum[] = $e;
echo array_sum($sum);
?>

---

You need to use && (AND) instead of || (OR).

if (isSet($a) && isSet($b) && ...) {
    //code
}

This can be simplified to

if  (isSet($a,b,$c,$d,$e)) {
    //code
}

---

You may ask why?

isset($a) || isset($b) || isset($c) || isset($d) || isset($e)

When you describe it in words it becomes clear:

$a is set OR $b is set OR $c is set

Only one condition needs to be true for the whole expression to evaluate to true (and since some others are false, you will get the notice). Whereas when you use && (AND), all expressions need to be true.

Answer 2

works fine on my pc but try

 echo ($a = array_sum($box_chrs));