Question

Why is the answer 5058? Again, what is printed is 5058. I want to know - in the least complicated way possible - why this is the answer. I need to know for a test.

Consider the following class public class IntegerArrayList {         private int[] array;     private int lastUnusedIndex;     public final static int DEFAULT_SIZE = 1000;         public IntegerArrayList() {         this(DEFAULT_SIZE);     }     public IntegerArrayList(int size) {         if (size < 1)             size = DEFAULT_SIZE;                 this.array = new int[size];         this.lastUnusedIndex = 0;     }         public int get(int index) {         if (index < 0 || index >= this.lastUnusedIndex)             return 0;                 return this.array[index];     }         public void add(int item) {                 this.array[this.lastUnusedIndex] = item;         this.lastUnusedIndex ++;                 if (this.lastUnusedIndex >= this.array.length)             makeArrayTwiceAsBig();             }         private void makeArrayTwiceAsBig() {         int[] temp = new int[this.array.length * 2];                 for (int i = 0; i < this.array.length; i++)             temp[i] = this.array[i];                 this.array = temp;     }         public int size() {         return this.lastUnusedIndex;     }         public int getInternalArraySize() {         return this.array.length;     } } What is printed on the console after the following lines execute? IntegerArrayList ial = new IntegerArrayList(2); ial.add(5); ial.add(3); ial.add(9); ial.add(12); ial.add(0); System.out.print(ial.get(0)); System.out.print(ial.get(-5)); System.out.print(ial.size()); System.out.print(ial.getInternalArraySize());

Answer 1

Explanation:

IntegerArrayList ial = new IntegerArrayList(2);
creates an array with size 2 and lastUnusedIndex=0

after the following lines execute
ial.add(5);
ial.add(3);
ial.add(9);
ial.add(12);
ial.add(0);

ial has array with length 8 and the content of array is [5, 3, 9, 12, 0, 0, 0, 0]
0 1 2 3 4 5 6 7 --> indices of array
                                                      
System.out.print(ial.get(0)); it prints 5 as output because 5 is present at 0th index of array.

System.out.print(ial.get(-5)); it prints 0 as output because if index < 0, get(int index) method return 0.

System.out.print(ial.size()); it prints 5 because size() method returns lastUnusedIndex which is 5.

System.out.print(ial.getInternalArraySize()); it prints 8 because getInternalArraySize() method returns array.length which is 8.

So the output is 5058