C++ classes

I am just starting out programming. I want to make a calculator for all the questions I will be asked in my trig class, but I only want this on my computer so I could try to learn trig and programming sort of together.

That's not why I am here though. I am here because classes confuse the fuck out of me. I do not understand how to "think" in terms of classes. Dereferencing pointers to public blah blah blah. It's all very weird. I was wondering if you guys knew anything that could distill the idea of how to think of classes and how to write them.

>>14
You'll notice the duck I used in my examples are Touring-complete. They can swim up and down an infinitely long river, and at any given stage they can:
1) Take a shit
2) Quack
3) Food