AP Computer Science: Assignment 1

ASSIGNMENT1.md

AP CS Assignment 1

Nicholas Hubbard

Natural Numbers, Naturally

Code:

public class NaturalNumberSeq {
	/**
	 * Find all natural numbers divisible by either 5 or 3 below 1,000.
	 * @return Integer result of sum of the relevant natural numbers
	 */
	public static int findNaturalNumberSum() {
		// Initialize the sum variable.
		int sum = 0;

		// Find all natural numbers, below the given maximum, which are divisible by either 3 or 5.
		for (int i = 0; i < 1000; i++) {
			if ((i % 3 == 0) || (i % 5 == 0)) {
				sum += i;
			}
		}

		// Output the result.
		return sum;
	}

	public static void main(String[] args) {
		int result = findNaturalNumberSum();
		System.out.println("The sum of all natural numbers below 1,000 which are divisible by 3 or 5 is: " + result);
	}
}

Result:

The sum of all natural numbers below 1,000 which are divisible by 3 or 5 is: 234168

Fibonacci Funnyness

Code:

import java.util.ArrayList;
public class FibonacciFunnyness {
	public static ArrayList<Integer> fibonacciEvens = new ArrayList<Integer>();
	/**
     * Find even-value Fibonacci results until a given maximum.
	 */
	public static int fibonacciEvenSum(int max) {
		// Initialize variables.
		int first = 0;
		int second = 1;

		// Find Fibonacci numbers, evens only.
		while (first <= max) {
			if (first % 2 == 0) {
				fibonacciEvens.add(first);
			}
			int sum = first + second;
			first = second;
			second = sum;
		}

		// Print the resulting array.
		System.out.println("DEBUG: " + fibonacciEvens);
		System.out.println("DEBUG: Number of items: " + fibonacciEvens.size());

		// Sum the resulting array.
		int finalSum = 0;
		for (Integer i : fibonacciEvens) {
			finalSum += i;
		}

		// Return the resulting sum.
		return finalSum;
	}

	public static void main(String[] args) {
		int result = fibonacciEvenSum(4000000);
		System.out.println("The sum of all even Fibonacci numbers below 4,000,000 is: " + result);
	}
}

Result:

DEBUG: [0, 2, 8, 34, 144, 610, 2584, 10946, 46368, 196418, 832040, 3524578]
DEBUG: Number of items: 12
The sum of all even Fibonacci numbers below 4,000,000 is: 4613732