Online PHP editor | output for mgSBn

<?php $a='5465574541345268975564654'; $b='2514523656557987'; echo "Normal sum : ".($a +$b); echo "\n"; $main_loop = strlen($a); if(strlen($a) < strlen($b)){ $main_loop = strlen($b); $a = str_pad($a,strlen($b),"0",STR_PAD_LEFT); } else { $b = str_pad($b,strlen($a),"0",STR_PAD_LEFT); } $carry = 0; $str = ""; $new_sum = ""; for($i = $main_loop-1;$i>=0;$i--) { $char_a = isset($a[$i])?$a[$i]:0; $char_b = isset($b[$i])?$b[$i]:0; $sum_char =(string)($char_a + $char_b + $carry); $carry = 0; $str = (string)$sum_char[0]; if(strlen($sum_char) > 1) { $carry = $sum_char[0]; $str = $sum_char[1]; } $new_sum .= $str; } $new_sum = strrev($new_sum); echo $new_sum;