Program to sum the digits of a number working fine for small numbers but not for larger-ones

Question

I am writing a program to sum the digits of a number , it is working fine for small numbers but for large no it is giving unexpected sum? below is the program.

<?php
ini_set('display_errors', 1);
error_reporting(E_ALL);
class demo {
    private $sum = 0;
    private $num = 0;
    private $rem = 0;

    public function digit_sum($digit) {
        //echo gettype($digit).'<br>';
        try {
            if (gettype($digit) == 'string') {
                throw new Exception($digit . ' is not a valid number <br>');
            } else {
                $this->num = $digit;
                while ($this->num > 0) {
                    $this->rem = $this->num % 10;
                    $this->sum = $this->sum + $this->rem;
                    $this->num = $this->num / 10;
                }
                return "Sum of no  $digit is = " . $this->sum . '<br>';
            }
        } catch (Exception $e) {
            echo $e->getMessage();
        }
    }

}

$sum = new demo();
echo $sum->digit_sum('sfsdfsdfds');
echo $sum->digit_sum(12345);
// outputs correct sum
echo $sum->digit_sum(3253435674);
//outputs incorrect sum

i see the above code results fine for integer no but not for double no' please guide me what will be the perfect solution to this problem?

http://stackoverflow.com/questions/670662/whats-the-maximum-size-for-an-int-in-php — Jeff, Oct 02 '16 at 12:39
Your code doesn't not provide correct value for 6 digit number too. — Naresh Kumar P, Oct 02 '16 at 12:42
This is why your code is failing http://stackoverflow.com/a/18055922/1415724 - `3253435674` is bigger than the maximum `2147483647` on a 32-bit machine. If you remove the `4` in there, you'll see your code will work as intended. — Funk Forty Niner, Oct 02 '16 at 14:14
@Fred-ii-, That's OK, I understood what you mean. But what about my detection?? Is the `$this->sum` not storing the previous sum?? — Murad Hasan, Oct 03 '16 at 08:35

Murad Hasan · Answer 1 · 2016-10-03T08:38:43.063

0

Do you know if you put a new echo $sum->digit_sum(32); The output will show you 62. Cause you create object once and call the same function multiple times. The object stores the sum for all the times.

Solution:

Just put an statement $this->sum = 0; before the while loop to clear the previous sum.

Online Example: https://3v4l.org/C7Yli.

Update: I tested the scripts in writephponline.com as per your comment and get the following result.

edited Oct 03 '16 at 08:38

answered Oct 02 '16 at 12:45

Murad Hasan

9,565
2
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42

yes you are right , but i have php 7 , $sum->digit_sum(3253435674) giving me 36 instead of 42. i am checking this code on http://www.writephponline.com/ and result is 42 for same code. – Atul Kumar Oct 02 '16 at 13:29
And what is in the output of the online example?? __Output for 5.6.0 - 5.6.26, hhvm-3.10.0 - 3.14.4, 7.0.0 - 7.1.0RC3__, In these versions the output will be same. – Murad Hasan Oct 02 '16 at 15:41

Program to sum the digits of a number working fine for small numbers but not for larger-ones

1 Answers1