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PHP Challenges: Compute the sum of the two reversed numbers and display the sum in reversed form

PHP Challenges - 1: Exercise-17 with Solution

Write a PHP program to compute the sum of the two reversed numbers and display the sum in reversed form.

Input : 13, 14

Note : The result will not be unique for every number for example 31 is a reversed form of several numbers of 13, 130, 1300 etc. Therefore all the leading zeros will be omitted.

Explanation :

PHP: Compute the sum of the two reversed numbers and display the sum in reversed form

Sample Solution :

PHP Code :

<?php
function reverse_sum($n1, $n2)
{
    return reverse_integer($n1) + reverse_integer($n2);
}

function reverse_integer($n)
{
    $reverse = 0;
    while ($n > 0)
      {
        $reverse = $reverse * 10;
        $reverse = $reverse + $n % 10;
        $n = (int)($n/10);
      }
     return $reverse;
}   
print_r(reverse_sum(13, 14)."\n");
print_r(reverse_sum(130, 1)."\n");
print_r(reverse_sum(305, 794)."\n");
?>

Sample Output: 

72                                                          
32                                                          
1000

Flowchart:

PHP Flowchart: Compute the sum of the two reversed numbers and display the sum in reversed form

PHP Code Editor:

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Previous: Write a PHP program to check a sequence of numbers is a geometric progression or not.
Next: Write a PHP program where you take any positive integer n, if n is even, divide it by 2 to get n / 2. If n is odd, multiply it by 3 and add 1 to obtain 3n + 1. Repeat the process until you reach 1.

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PHP: Tips of the Day

How to Sort Multi-dimensional Array by Value?

Try a usort, If you are still on PHP 5.2 or earlier, you'll have to define a sorting function first:

Example:

function sortByOrder($a, $b) {
    return $a['order'] - $b['order'];
}

usort($myArray, 'sortByOrder');

Starting in PHP 5.3, you can use an anonymous function:

usort($myArray, function($a, $b) {
    return $a['order'] - $b['order'];
});

And finally with PHP 7 you can use the spaceship operator:

usort($myArray, function($a, $b) {
    return $a['order'] <=> $b['order'];
});

To extend this to multi-dimensional sorting, reference the second/third sorting elements if the first is zero - best explained below. You can also use this for sorting on sub-elements.

usort($myArray, function($a, $b) {
    $retval = $a['order'] <=> $b['order'];
    if ($retval == 0) {
        $retval = $a['suborder'] <=> $b['suborder'];
        if ($retval == 0) {
            $retval = $a['details']['subsuborder'] <=> $b['details']['subsuborder'];
        }
    }
    return $retval;
});

If you need to retain key associations, use uasort() - see comparison of array sorting functions in the manual

Ref : https://bit.ly/3i77vCC