What is counter?? What is max_index?? I'm so lost

Question

while counter <= max_index:

Answer 1

counter and max_index are variable that contain a value, so the value in the counter is been checked if its less than or equally to the value of max_index

Answer 2

I prefer a tag pointing about which language you're talking about.🙃thankyou

Answer 3

Variables that must have been defined before this code of line, they can be anything though, but those two samples are used frequently by coders.