An annoyance with the Arduino IDE is the need to shut down the serial port terminal when you want to upload new code. The Eclipse solution manages this while keeping the terminal window open.

It turns out that the Arduino code doesn’t wait for the first, garbage, result to finish before starting the next one. That is enough to cause the observed offset issue.

Although Arduino's programming language is based on C++, you won't be able to use all of its commands. But, you can still use objects in Arduino's IDE, which are a fundamental aspect of C++.