title: PHP Storing functions
body: <p>How do these 2 variables get utilised in the code?:</p>
  <pre><code>$run1 &amp; $run2
  </code></pre>
  <p>I was told they store the functions results,
  however the echo command doesn't utilise them.
  Is it because the code uses &quot;assign by reference&quot; that they need to be there ?
  or what is the ultimate purpose of these</p>
  <pre><code>function f1(&amp;$array_para)
  {
      $array_param[&quot;a&quot;] = &quot;changed&quot;;
  }
  
  function f2($array_param)
  {
      $return_arr = f1($array_param);
      return $return_arr;
  }
  
  $arr1 = [&quot;a&quot; =&gt; &quot;Tadpole&quot;];
  $arr2 = [&quot;a&quot; =&gt; &quot;Lily&quot;];
  $run1 = f1($arr1);
  $run2 = f2($arr2);
  echo $arr1[&quot;a&quot;] . &quot; &quot; . $arr2[&quot;a&quot;];
  </code></pre>