#include<iostream>
using namespace std;

//Part 1: area of a recatngle
//Area = height * width
double area (double height, double width)
{
	return height*width;
}

//Part 2: function to find the fatcorial of a number.
//Factorial = product of all numbers from 1 to the number
long factorial (int num)
{
	long fact = 1;
	for( int i=1; i<=num; i++)
		fact = fact * num;
	return fact;
}

int main()
{
	double h,w;
	cout<<"Enter the height of the rectangle: ";
	cin>>h;
	cout<<"Enter the width of the rectangle: ";
	cin>>w;

	cout<<"The area is "<<area(h,w)<<endl;

	int n,k;
	cout<<"Enter the value of n: ";
	cin>>n;
	cout<<"Enter the value of k: ";
	cin>>k;

	long nChoosek = factorial(n) / (factorial(k) * factorial(n-k));
	// We are ok with integer division because binomial coefficients are always integers.
	// There is a big proof on the internet if you're interested.
	// https://proofwiki.org/wiki/Binomial_Coefficient_is_Integer
	return 0;
}