Design and implement a program that creates an exception class
called , designed to be thrown
when an improper designation for a document is encountered
during processing. suppose in a particular business all documents
are given a two-character designation starting with either u, c,
or p, standing for unclassified, confidential, or proprietary. if a
document designation is encountered that doesn’t fit that description,
the exception is thrown. create a driver program to test the
exception, allowing it to terminate the program.

Suppose there is a relation r(a, b, c) with a b+-tree index with search keys (a, b).1. what is the worst-case cost of finding records satisfying 10 < a < 50 using this index, in terms of the number of records n1, retrieved and the height h of the tree? 2. what is the worst-case cost of finding records satisfying 10 < a < 50 and 5 < b < 10 using this index, in terms of the number of records n2 that satisfy this selection, as well as n1 and h defined above? 3. under what conditions on n1 and n2, would the index be an efficient way of finding records satisfying the condition from part (2)?