I apologize beforehand for this noobish Q, but Im starting to learn C++, and have only used Java.
I have also searched here and elsewhere for a solution to this and
g++ is installed as part of MinGW. If you are getting an error in Eclipse that it cannot find g++ then your path is most likely incorrect. From a command prompt you should be able to run:
g++ --version
and it should display the version of g++ in the MinGW/bin directory.
Eclipse uses this path to locate the include files and the compiler. Once you get the path correct restart Eclipse and the problems listed in your question should be resolved.