FilterList.java

import java.util.Arrays;
import java.util.List;
import java.util.ArrayList;

public class FilterList {
	// Write a function named "evens" that takes as input a
	// list of Integer (almost but not quite int) and returns
	// a new list of ints containing only the even elements
	// of the input.
	public static List<Integer> evens(List<Integer> input) {
		// Here are some reminders:
		//
		// You can find input's length using input.size().
		//
		// You can find the remainder of a division using %. For instance,
		// 2 == 11%3 and 1 == 25 % 4.
		//
		// You can declare a new list named "clown" of length n with the
		// syntax:
		//
		// List<Integer> clown = new ArrayList<Integer>(10);

		// STUDENTS, WRITE CODE HERE.
		List<Integer> evenNums = new ArrayList<Integer>();

		for (Integer i : input)
			if (i % 2 == 0)
				evenNums.add(i);

		return evenNums;
	}

	public static void main(String[] args) {
		List<Integer> test1 = new ArrayList<Integer>(Arrays.asList(8, 6, 7, 5,
				3, 0, 9));
		List<Integer> ans = evens(test1);
		// Expected output: 8, 6, 0
		for (Integer n : ans) {
			System.out.print(Integer.valueOf(n) + ", ");
		}
		System.out.println();

		List<Integer> test2 = new ArrayList<Integer>(Arrays.asList(2, 7, 18,
				28, 18, 28, 45, 90, 45));
		ans = evens(test2);
		// Expected output: 2, 18, 28, 18, 28, 90
		for (Integer n : ans) {
			System.out.print(Integer.valueOf(n) + ", ");
		}
		System.out.println();

		// STUDENTS: ADD YOUR TEST CASES HERE.
		List<Integer> test3 = new ArrayList<Integer>(Arrays.asList(99, 99, 813, 223));
		ans = evens(test3);
		// Expected output: 
		for (Integer n : ans) {
			System.out.print(Integer.valueOf(n) + ", ");
		}
		System.out.println();
		
		List<Integer> test4 = new ArrayList<Integer>(Arrays.asList(2, 45, 90, 45));
		ans = evens(test4);
		// Expected output: 2, 18, 28, 18, 28, 90
		for (Integer n : ans) {
			System.out.print(Integer.valueOf(n) + ", ");
		}
		System.out.println();
	}
}