For others looking for a solution to this problem - you should checkout:
http://oneqonea.blogspot.com/2012/04/how-do-i-add-syntax-highlighting-to-my.html
It's a really easy "SyntaxHighlighter for Blogger" tutorial with screenshots and everything.
You should be up and running in only a few minutes.
Also, for your C++ application, make sure you have the shBrushCpp.js library referenced in your <head></head> section like this:
<head>
<script src='http://alexgorbatchev.com/pub/sh/current/scripts/shBrushCpp.js' type='text/javascript'/>
</head>