tute04.cpp

/*Exercise 4 - Functions

Write a program to calculate the function called nCr which is defined as

nCr = n!/ r!(n−r)!
Where n! is the factorial of n.

Implement the functions

long Factorial(int no);
long nCr(int n, int r);
Do not modify the main function.*/

#include <iostream>

long Factorial(int no);
long nCr(int n, int r);

int main() {
  int n, r;
  std::cout << "Enter a value for n ";
  std::cin >> n;
  std::cout << "Enter a value for r ";
  std::cin >> r;
  std::cout << "nCr = ";
  std::cout << nCr(n,r);
  std::cout << std::endl;
  return 0;
}
long Factorial(int no)
{
  int res = 1;
  for (int i = 2; i <= no; i++)
  res = res * i;
  return res;
}
long nCr(int n , int r)
{
   return Factorial(n) / (Factorial(r) * Factorial(n - r));
}