[6 points] Write a program that uses some aspect of macros (section 4.9) to compute the value of permutations and combinations as defined below: 3. n! n! C (n, k) = k!(n - k)! Note that n and k are positive integers that should be input by the user. Problem 32 and 33 on page 211 of your textbook has further detail about the above two functions 4. [3 points] Short Answer Questions: Describe the key differences between global and local variable. What are the advantages of using functions in a program? When is it not necessary to declare a function in the main? a. b. c