How to generate numbers whose sum of digits is equal to a given number?

Question

Algorithms

The task is: Given an input number, output a set of numbers whose sum of digits is equal to this number, and the numbers must be different.
I ask for help in building an algorithm for generating such numbers, Or, if it has already been decided somewhere, links to this resource.

Answer 1

<?php

$number = 100;
$a=1;
$b = $number - $a;

for ($i = 1; $i < $number; $i++) {
  if ($a != $b) {
    echo $a . '+';
    echo $b . '|';
    $a++;
    $b--;
  }
}

The truth does not take into account the permutation of the terms