#include <iostream>


using namespace std;


//get user input: 
// int get_input() {
// 	int input;
// 	cout << "Enter an int: ";
// 	cin >> input;

// 	if (!valid(input))
// 		//get the user input again
// 		get_input();
// 	return input;
// }


int fact_iter (int n) {
	if (n == 0)
		return 1;
	int fact = n;
	for (int i = 1; i < n; ++i)
	{
		fact = fact * i;
	}
	return fact;
}

int fact_recur(int n) {
	//base case:
	if (n == 0)
		return 1;

	return n * fact_recur(n-1);
}

int pwr_iter (int base, int exp){
	int result = 1;
	for (int i = 0; i < exp; ++i)
	{
		result = result * base;
	}
	return result;
}

//Assuming both 'base' and 'exp' are >= 0
int pwr_recur (int base, int exp){
	//FIXME:
	//base case: 
	if (exp == 0) 
		return 1;
	//recursive calls: 
	// base^exp = base * base^(exp-1);
	// i.e., 2^10 = 2 * 2^9
	//            = 2 * (2 * 2^8)

	return base * pwr_recur(base, exp-1);
}

int main(int argc, char const *argv[])
{
	cout << fact_iter(10) << endl;
	cout << fact_recur(10) << endl;


	cout << pwr_iter (2, 16) << endl;
	cout << pwr_recur (2, 16) << endl;
	return 0;
}