phyton but first you need a Raspperry PI usb you can visit their website with phyton code examples
just Google :rasperry PI....
and buy their usb just only at 13 or 20 dolar is cheap and useful to create a robot or drone control
one more things NASA also used phyton to create a robot and get the data on space with phyton and rasperry PI ...u can learn on YouTube how to use them. ...is easy. ..
don't forget to get master at phyton first
for programming devices in c++,
is a good place. You did not say which roboter.
The kind of coding depends: Some robots have a high level API. For some you have to code on sensor/actor level.