// Oldham, Jeffrey D.
// 1999 Oct 25
// CS1320
//
// Compute the Binomial Coefficient of Two Values

// The user is queried for n and k.
// The value of $n \choose k$ is printed.  $n$ and $k$ are swapped is
// necessary.

#include <iostream.h>

// Function Prototypes
int combination(const int n, const int k);
int factorial(const int n);
void obtainInput(int& n, int& k);
void swap(int& first, int& second);

int main()
{
  int n, k;
  obtainInput(n,k);
  cout << combination(n,k) << endl;
  return 0;
}

int combination(const int n, const int k)
{
  return factorial(n) / (factorial(k) * factorial(n-k));
}

int factorial(const int n)
{
  int product = 1;
  int index;
  for (index = n; index > 0; --index)
    product *= index;
  return product;
}

void swap(int& first, int& second)
{
  int temp = first;
  first = second;
  second = temp;
  return;
}

void obtainInput(int& n, int& k)
{
  cout << "Please enter n and k for (n choose k): ";
  cin >> n >> k;

  if (n < k)
    swap(n,k);
  return;
}