More information would be helpful.
The title says it all.
First; if you are programming in C++ what is with the *.h files?
Second; an intro to computer science course should have set you up to understand the building of a program.
Third; While I don't see Eclipse as being that much worst than XCode i do agree with the idea that it really pays in the long run to learn to program with a simple text editor and build a program from the command line. Back to Eclipse in many ways it is a better system than XCode, XCode is very easy to get into crash-a-matic mode. Of course updating Eclipse can do that for you two.
Fourth; we are assuming you are programming on a Mac, but it would really help if you spelt it out. Frankly, your post leaves people with the impression that you haven't even tried as there is no usable detail at all in the text.
Fifth; everybody has already mentioned that Mac OS comes with XCode and the associated development tools.
Finally as far as what to keep in mind when writing the program? Well you might want to consider why you are in the class in the first place.
Dave