// Fibonacci Series and Factorial Code
// Jon F.
// Last Modified: 11/1/2013

// needed libraries/modules
#include <iostream>
#include <vector>
using namespace std;

// factorial as a loop
long int factorial_loop(long int number)
{
    // keep track of the answer
    long int answer = 1;
    
    // generate a vector with space for a numerical range of 2 -> n + 1
    // range is 0 based from 0 -> number - 1
    // and pads the vector with zeroes
    vector<long int> range((number + 1) - 2, 0);
    
    // generate an object to iterate over the vector
    vector<long int>::iterator in_range;
    
    // for all items in the vector
    for (auto in_range = range.begin(); in_range != range.end(); in_range++)
    {
        // get the current index of the iterator as a number
        long int current_index = in_range - range.begin();
        
        // set the vector item at that index to the start of the first item
        // plus the index of that item in the current vector
        // (skips the first element and creates a list of 2 -> number)
        *in_range = (answer + 1) + current_index;
    }
    
    // for i in range vector multiply the answer by i
    for (auto &i : range) answer *= i;
    
    // return the answer
    return answer;
}

// recursive factorial
long int factorial (long int number)
{
    // factorial returns 1, else higher number multiplied
    // by the number below it
    if (number == 1) return 1;
    else return number * factorial(number - 1);
}

// recursive fibonacci
long int fibonacci (long int number)
{
    // fibonacci returns 0, 1, or the last two values added
    if (number == 0) return 0;
    else if (number == 1) return 1;
    else return fibonacci(number - 1) + fibonacci(number - 2);
}

// driver
int main(int argc, const char * argv[])
{
    // factorial driver
    cout << "12 Factorial: " << endl;
    cout << "Loop: " << factorial_loop(12) << endl;
    cout << "Recursion: " << factorial(12) << endl << endl;
    
    // fibonacci driver
    cout << "12th Fibonacci Number: " << endl
    << fibonacci(12) << endl;
}