documentation/bubblesort.html


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<h1>How fast is a C++ extension</h1>
<p>
    Native extensions are fast. But how fast are they? We can demonstrate this
    with a very simple extension: bubblesort.
</p>
<p>
    Bubblesort is a very inefficient sorting algorithm that is never used in
    real world software - but that is often used in universities to demonstrate
    algorithms. We will show you an implementation of this algorithm in PHP
    and in C++ - and see how much faster the C++ code is.
</p>
<p>
<pre class="language-php">
&lt;?php
 
/**
 *  Bubblesort function in parameter
 *
 *  This function takes an unsorted array as input, sorts it, and returns
 *  the output. It only uses normal PHP operation, and does not rely on
 *  any builting PHP functions or on functions from extensions
 *
 *  @param  array       An unsorted array of integers
 *  @return array       A sorted array
 */
function bubblesort(array $input)
{
    // number of elements in the array
    $count = count($input);
    
    // loop through the array
    for ($i = 0; $i &lt; $count; $i++)
    {
        // loop through the elements that were already processed
        for ($j = 0; $j &lt; $count - $i; $j++)
        {
            // move on if smaller
            if ($input[$j] &lt;= $input[$j+1]) continue;
    
            // swap elements
            $temp = $input[$j];
            $input[$j] = $input[$j+1];
            $input[$j+1] = $temp;
        }
    }
}
?&gt;