The charAt method retrieves the character at a specified index within a string.
CharAt cheat sheet for homework
An index is a position within an array or string. It starts from 0 and goes up to length-1.
A substring is a portion of a string extracted based on starting and ending indices. It allows you to isolate specific parts of text within larger strings.
Length refers to the number of characters in a string. For example, "Hello" has length 5.