Exercise 05

1. If I wanted to print the first element in an array, how would I do it?

2. If I wanted to iterate through a basic Java array, how would I do it? Would I use the ".length" property or the ".size()" method?

3. If I wanted to iterate through Java's ArrayList, how would I do it? Would I use the ".length" property or the ".size()" method?

4. True or False: I would use Java's basic array when I know the size of the data or the array will not change, and I should use Java's ArrayList when I need a dynamic array and I don't know how much data may or may not be added.

5. What will happen if I try to access an element in a basic array at the index of -1 like so:

int[] array = {1, 2, 3, 4, 5}; inttest = array[-1];

6. What will the following code print?

int[] array = {2, 4, 6, 8, 10};

int test = array[5];

System.out.println(test);

7. The code below prints out something like this:

[I@626b2d4a

[1, 2, 3, 4, 5]

Why does printing a basic Java array print something that seems random while Java's ArrayList prints the data in the array in a readable way?

public static void main(String[] args) {

int[] array = {1, 2, 3, 4, 5};

ArrayList arrayList = new ArrayList(Arrays.asList(1, 2, 3, 4, 5));

System.out.println(array);

System.out.println(arrayList);

}

8. What is printed in the following code? (HINT: I am not passing a primitive type, but an ArrayList.

public static void main(String[] args) {

ArrayList list = new ArrayList();

System.out.println(list);

add5Numbers(list);

System.out.println(list);

}

public static void add5Numbers(ArrayList list) {

list.add(1);

list.add(2);

list.add(3);

list.add(4);

list.add(5);

System.out.println(list);

}