Write a program that creates a ProfessorRating class consisting of
professor ID and three ratings. The three ratings are used to evaluate
easiness, helpfulness, and clarity. In a separate implementation class, allow
the user to enter the values. Call the constructor to create an instance of the
ProfessorRating class. Include appropriate properties. Do not allow
the ID to be changed after an object has been constructed. Provide a
method in the ProfessorRating class to compute and return the
overall rating average. Print all ratings and the average rating formatted with
no digits to the right of the decimal from the implementation class. Use a
single class method to enter all data.