import org.junit.Test;

import static junit.framework.TestCase.assertEquals;

/**
 * Generic test class for implementing and testing a sequence in recursive and iterative form
 *                _ _   _               _
 * __      ___ __(_) |_| |_ ___ _ __   | |__  _   _
 * \ \ /\ / / '__| | __| __/ _ \ '_ \  | '_ \| | | |
 *  \ V  V /| |  | | |_| ||  __/ | | | | |_) | |_| |
 *   \_/\_/ |_|  |_|\__|\__\___|_| |_| |_.__/ \__, |
 *                                            |___/
 *  ____                  __     __               _
 * / ___|_   _____ _ __   \ \   / /__   __ _  ___| |
 * \___ \ \ / / _ \ '_ \   \ \ / / _ \ / _` |/ _ \ |
 *  ___) \ V /  __/ | | |   \ V / (_) | (_| |  __/ |
 * |____/ \_/ \___|_| |_|    \_/ \___/ \__, |\___|_|
 *                                     |___/
 * Licensed under the GPLv2 License, Version 2.0 (the "License");
 * Copyright (c) Sven Vogel
 */
public class Aufgabe5 {

    /**
     * Calculate some recursive sequence
     * @param n the number to calculate the sequence of
     * @return the value for the given number of the sequence
     */
    private static int recursiveFunction(int n) {
        if (n <= 0) {
            return 1;
        } else if (n == 1) {
            return 2;
        }

        return 4 * recursiveFunction(n - 2) - 1;
    }

    /**
     * Calculate some iterative sequence
     * @param n the number to calculate the sequence of
     * @return the value for the given number of the sequence
     */
    private static int iterativeFunction(int n) {
        if (n <= 0) {
            return 1;
        } else if (n == 1) {
            return 2;
        }

        int sum = 1;
        for (int i = 2; i < n; i += 2) {
            sum = sum * 4 - 1;
        }

        return sum;
    }

    @Test
    public void test() {
        assertEquals(recursiveFunction(0), 1);
        assertEquals(recursiveFunction(1), 2);
        System.out.println("greater than 1: " + recursiveFunction(12));
        assertEquals(recursiveFunction(67), iterativeFunction(67));
    }
}