Officially notepad++ is not supported for ubuntu.
However you can install it via wine and run through it!

If you don't have wine just type in terminal

sudo apt-get install wine

Then go to notepad++'s website and download the latest version.
Run in in ubuntu with wine(right click the .exe and select open with wine).

Check this video, that will help you.

Alternatively, you can use geany which can be used either in windows or ubuntu.
It's a really cool editor, that can also be use for LaTeX.

Here you can see a C++ code screenshot from geany