Chapter 6.4, Problem 6.4.8CP

Write method headers (not the bodies) for the following methods:

1. a. Return a sales commission, given the sales amount and the commission rate.
2. b. Display the calendar for a month, given the month and year.
3. c. Return a square root of a number.
4. d. Test whether a number is even, and returning true if it is.
5. e. Display a message a specified number of times.
6. f. Return the monthly payment, given the loan amount, number of years, and annual interest rate.
7. g. Return the corresponding uppercase letter, given a lowercase letter.