User:Shyal-b/Sandbox/combinations

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#include <iostream>
#include <vector>

using namespace std;

double factorial(int a)
{
         double r = a;
         if (a > 0)
         {
                 while (--a)
                 {
                         r *= a;
                 }
         }
         else
         {
                 r = 1;
         }
         return r;
}

int combinations(int n, int r)
{
         return((int)(factorial(n)/(factorial(n-r)*factorial(r))));
}

int main()
{
         int n, r;
 
         cout << "Enter any n and r to compute its combinations" << endl;
 
         cout << "n : "; cin >> n;
         cout << "r : "; cin >> r;
 
         long p = combinations(n, r);
 
         cout << "combinations : " << p << endl;

         return 0;
}