Question: Implement some of the following improvements to the string class.
a. Add ! (which is false if the string is zero length).
b. Add the * and * = operators to expand into multiple copies. For instance, if s is equal to " ab" , then s * =3 turns s into " ababab" .
c. Add the left shift operator, which shifts the string x positions. Can you think of a way to alter the class implementation to make shifting a fast operation?
d. Add lowercase and uppercase member functions.