ReorMadrid

To use it, you must use the [code] shortcode like this:
PHP Code Example:
[easycode] 
< ? php 
e cho “Hi, world!”; 
 ? > 
[/easycode]
In the admin menu, you have options to change the background colors, button colors, language and more.

Easy Code Highlighter

Displays code with syntax highlighting using Prism.js, real line numbering, and a copy button.

Darshan Sawardekar

WP-Syntax-Highlighter is a WordPress plugin that brings the <a href="http://highlightjs.org" rel="nofollow ugc">Highlight.js</a> based source code syntax 
highlighting to WordPress. This plugin is compatible with any other syntax highlighter 
plugins that use <a href="http://alexgorbatchev.com/SyntaxHighlighter/" rel="nofollow ugc">Syntax Highlighter</a>, <a href="http://qbnz.com/highlighter/" rel="nofollow ugc">GeSHi</a> 
or <a href="http://prismjs.com" rel="nofollow ugc">Prismjs</a>.
<h3>Credits</h3>
<ul>
<li>Thanks to Ivan Sagalaev and the <a href="http://highlightjs.org/" rel="nofollow ugc">highlight.js</a> team for this excellent library.</li>
</ul>

wp-syntax-highlighter

Syntax Highlighter for WordPress using Highlight.js.

Easy Code Highlighter vs wp-syntax-highlighter