If the question had been tagged [tag:c], your code block would have worked. But, it wasn't. 

You could *add* the tag, I suppose... But that seems lame, since the question wasn't *about* C. 

So your next best option is to simply [force syntax highlighting for your code block](https://meta.stackexchange.com/questions/63800/interface-options-for-specifying-language-prettify), by prefixing it with a special comment:

    <!-- language: lang-c -->

        ... code goes here, indented by four spaces as usual ...

I've done this for you. Enjoy!