Question

When finding a substring in the String class, do you start counting at 0 or at 1?

Answer 1

We start at 0 for substring and almost all the formulas except length() where we actually count(start at 1).

Answer 2

String's characters start at 0.
An example would be:
0 = H
1 = e
2 = l
3 = l
4 = o