It is almost never appropriate to put code in your slides, psudo-code or not. This has nothing to do with the level of technical finesse of your slides, and everything to do with whether or not it is a good presentation that your audience can follow. Most of the time, you will want to represent your ideas graphically, not textually.
A slide-based presentation is a visual medium, supplemented by what you have to say about each slide. The content should largely be bold-print headers and visual representations of your concept - not large chunks of text that your audience is not likely to read in the time it is on the screen anyway.
One case in which you could justify the inclusion of code is if you plan to go over each step of the code line-by-line, or as a side-by-side comparison, and then only if you are willing to guide your audience through every single step, preferably with a laser pointer or other type of pointer to indicate how each part of the code is relevant.
Even then, I would not recommend including more than a few lines of code - text is very difficult to focus on during a presentation when the presenter is speaking, unless they are explaining the text to the viewer. The larger the block of text, the more explanation will be required, and the less interest your viewers will have.
As a technical presentation, if it is strictly necessary to include an example, then there is no question - you will have to include it, and find a way to explain it within your allotted presentation time. But if you have the option, a visual representation with a flowchart or some other graphic medium would be better suited to a slide-presentation style.
(Note: If it is not actually a 'presentation' and is meant to be a handout to others, disregard this and include some examples, but do not go over them too much during the actual presentation unless absolutely required.)