Using c++ data structures - please explain how many combinations and what the combinations would be. I am trying to understand the steps as well as the answer.

The first problem considered here is a function, Combinations, that tells us how many combinations of a certain size can be made from a total group of elements. For instance, if we have 20 different books to pass out to 4 students, we can easily see that,to be equitablewe should give each student 5 books. But how many combinations of 5 books can be made from a group of 20 books? A mathematical formula can be used for solving this problem. Given that Cis the total number of combinations, group is the total size of the group from which to pick, members is the size of each subgroup, and group>= members. C(group, members) = group, if members = 1 1, if member = group C(group -1, members 1 )+C(group 1, members), if group > members >1 Because this definition of Cis recursive, it is easy to see how a recursive function could be used to solve the