Given integers n and r where r <= n, generate

1. all P(n, r) permutations (corresponding to selecting r out of n distinct objects without repetition)

2. all n^r permutations (corresponding to selecting r out of n distinct objects with repetition)

in which the order is relevant; and

3. all C(n, r) combinations (corresponding to selecting r out of n distinct objects without repetition)

4. all C(r+n-1, r) combinations (corresponding to selecting r out of n distinct objects with repetition)

in which the order is irrelevant.