Welcome to the forums. In the future, try to place your threads more accordingly to the subject. As you made a question, this fits better in Linux - Newbie, then here. Ask a mod to move it there (do not double post).
With that in mind, the portability of your c/c++ code is how you wrote it. If you've used a lot of non-standand compliant code, as functions like "getch()", very popular in C++ books and dos compilers headers, you can trow it away and start from scratch. It simply will be too much hassle to "get 'em working" in Linux.
Another tip, try to be as descriptive as possible. Posting a simple program you made or even the commands you've tried to use in order to compile you program with gcc or g++ would have been of great help.
You might want as well to check this thread out: