There is a version of the Eclipse IDE out there at https://eclipse.baeyens.it/ that is all ready for the Atmel 328P chipset. It’s name is Sloeber. I am touting its praises even though I am still getting adjusted to using it. Installation was not difficult even though I had to adjust my file paths. The biggest difficulty was telling it not to be too smart. I also didn’t succeed in getting avrdude to work yet. But it handles multiple C++ files just like any Eclipse project and beautifully!