Write a program that keeps track of a speaker's bureau. The program should use a structure to store the following data about a speaker:

Name
Telephone Number
Speaking Topic
Fee Required

The program should use an array of at least 10 structures. It should let the user enter data into the array, change the contents of any element, and display all the data stored in the array. The program should have a menu-driven user interface.
Input Validation: When the data for a new speaker is entered, be sure the user enters data for all the fields. No negative amounts should be entered for a speaker's fee.