Index

An individual character is always identified by its index, also referred to as subscript, that is, its position in the string.

The first character will always have an index value of 0, the second an index of 1, and so on. The last character in a string always has an index of array.length() – 1

Sources:

Svetlin Nakov & Co Fundamentals of computer programming with C#: Sofia, 2013 - 1122 с. - 100