Write a program that asks the user for a sentence and then switches all lowercase letters to uppercase and vice versa. You will accomplish the same task in two different ways. In the first case, use character functions tolower() and toupper() to make the change. In the second case, use character arithmetic to make the change (hint: find an ASCII table and find out how much to add/subtract as needed to change from A to a, B to b, etc). You will need to use casting for this part. Display both results they should be the same.