I work primarily on my desktop, but I started working on my mac laptop and noticed a problem with eclipse CDT. The standard library was underlined yellow and cout wouldn't work (It wouldn't recognize/find it). I tried restarting the program and that didn't work. I then tried to see if xcode would work, found that the version of xcode was too old, and updated xcode. Eclipse still didn't work, but xcode did. I tried re-installing eclipse to the new version and re-installing cdt. It still wouldn't work. Restarting my computer wont work either. I'm not sure if this helps (or even matters/applies) but when I type g++ --version into terminal, it doesn't work. (I don't know if that matters but some tutorial told me to do that to check if the compiler was working).

So, in review, I have:

1. Re-installed eclipse
2. Restarted my computer
3. Re-installed xcode (which I think has all the compilers eclipse uses.)
4. Updated Eclipse
5. Typed g++ --version to test compiler.