Write the following methods.

a. int firstDigit(int n), returning the first digit of the argument

b. int lastDigit(int n), returning the last digit of the argument

c. int digits(int n), returning the number of digits of the argument

For example, firstDigit(1729) is 1, lastDigit(1729) is 9, and digits(1729) is 4. Provide a program that tests your methods.