Permutations of size k. Modify Permutations from the previous exercise so that it takes two command-line arguments n and k, and prints all P(n, k) = n! / (nk)! permutations that contain exactly k of...

Permutations of size k. Modify Permutations from the previous exercise so that it takes two command-line arguments n and k, and prints all P(n, k) = n! / (nk)! permutations that contain exactly k of the n elements. Below is the desired output when k = 2 and n = 4 (again, do not worry about the order):