Implement the ADT character string as the class Linked String by using a Linked list of characters. Include the following Lankest ing constructors and methods:

Returns a new linked character string that is a substring of this linked character string.

Implement Linked String so that it is consistent with the String class. For example, character positions start at zero. Also, keep track of the number of characters in the string; the length should be determined without traversing the linked list and counting.