to build on jtara's reply, use the built-in plugin manager:
- go to the eclipse menu: help > install new software.
- at head of the "Available Software" window, in "work with" box type or paste the url,
http://archive.eclipse.org/tools/cdt/releases/juno/.
- find CDT, or c++ packages, and install.
* alternatively *
- go to the eclipse menu: help > install new software.
- at head of the "Available Software" window click the drop down menu in "work with" box.
- choose "--All Available Sites--".
- a list of packages will be presented; check off "CDT main feature;" and "CDT optional feature."
- let the dialogue boxes guide your install.