Function Parameters in PHP: A Comprehensive Guide

Function parameters are declared after the function name and inside parentheses. They are declared much like a typical variable would be -

Syntax:

<span class="pln">

</span><span class="pun">&lt;?</span><span class="pln">php
   </span><span class="com">// multiply a value by 5 and return it to the caller</span><span class="pln">
   </span><span class="kwd">function</span><span class="pln"> multiply </span><span class="pun">(</span><span class="pln">$value</span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
      $value </span><span class="pun">=</span><span class="pln"> $value </span><span class="pun">*</span><span class="pln"> </span><span class="lit">5</span><span class="pun">;</span><span class="pln">
      </span><span class="kwd">return</span><span class="pln"> $value</span><span class="pun">;</span><span class="pln">
   </span><span class="pun">}</span><span class="pln">
   
   $retval </span><span class="pun">=</span><span class="pln"> multiply </span><span class="pun">(</span><span class="lit">10</span><span class="pun">);</span><span class="pln">
   </span><span class="typ">Print</span><span class="pln"> </span><span class="str">"Return value is $retval\n"</span><span class="pun">;</span><span class="pln">
</span><span class="pun">?&gt;</span><span class="pln">

</span>

Output:

This will produce the following result

<span class="pln">

</span><span class="typ">Return</span><span class="pln"> </span><span class="kwd">value</span><span class="pln"> </span><span class="kwd">is</span><span class="pln"> </span><span class="lit">50</span><span class="pln">

</span>