Question

Write a generic array list class. Task Description Your goal for this lab is to write a generic ArrayList class similar to the one in the given lecture notes on array lists. The ArrayList Class The public constructors and methods required for the ArrayList class are listed here. The type E is the generic type of an element of the list. ArrayList() Construct an empty ArrayList object. int size() Return the size (number of items) in this ArrayList. boolean isEmpty() Return true if this ArrayList has no items. (This is the same as the size equal to zero.) Return false if the size is greater than zero. void add(E value) Add the given element, value, to the end of the list. void add(int index, E value) Add the given element, value, to the list at the given index. After this operation is complete, get(index) will return value. This operation is only valid for 0 <= index <= size(). E get(int index) Return the element of the list at the given index. This operation is only valid for 0 <= index < size(). This operation does not modify the list. E remove(E value) Removes and returns the first occurrence of the specified element from this list, if it is present. E remove(int index) Remove and return the element with the given index from the list. This operation is only valid for 0 <= index < size(). After this operation, all elements that had an index greater than index (as determined by get()) will have their index reduced by one. void clear() Removes all the elements from this list. Requirements 1. Your class must be named ArrayList. 2. Your class must provide the methods listed above for construction, accessing, and manipulating ArrayList objects. 3. Other than for testing purposes, your ArrayList class should do no input or output.

Answer 1

import java.util.Random;

public class MyArrayList<E> {

// YOUR CODE ANYWHERE IN THIS CLASS

private Object[] array;

public static final int CAPACITY = 4;

public int size;

public int capacity;

// there could be more instance variables!

/*

* initialise array with capacity. If capacity is less than 1, use CAPACITY.

*

*/

@SuppressWarnings("unchecked")

public MyArrayList() {

array = new Object[CAPACITY];

this.capacity = 4;

size = 0;

}

public MyArrayList(int capacity) {

array = new Object[capacity];

this.capacity = capacity;

size = 0;

}

public void add(int i, E val) {

if (i >= capacity)

return;

else

{

size++;

for (int x = size - 1; x > i; x--) {

array[x] = array[x - 1];

}

array[i] = val;

}

}

public void add(E x) {

if (size >= capacity){

Object[] temp = new Object[2*(array.length)];

for(int i=0;i<size;++i){

temp[i] = array[i];

}

this.capacity = 2*array.length;

array = temp;

array[size++] = x;

return;

}

else

{

array[size++] = x;

}

}

public void set(int i, E val) {

// YOUR CODE ANYWHERE IN THIS CLASS

if (i >= capacity)

return;

else

{

size++;

for (int x = size - 1; x > i; x--) {

array[x] = array[x - 1];

}

array[i] = val;

}

}

/*

* if index is outside range of array. return null

*

*/

public Object get(int i) {

// YOUR CODE ANYWHERE IN THIS CLASS

if (i >= capacity)

throw new ArrayIndexOutOfBoundsException();

else

return array[i];

}

/*

* if index is outside range of array. return null

*

*/

public void remove(int i) {

if (i >= size || size == 0)

return;

else {

Object e = array[i];

for (int x = i; x < this.array.length - 1; x++) {

array[x] = array[x + 1];

}

size--;

}

}

public void remove(E ob) {

// YOUR CODE ANYWHERE IN THIS CLASS

if (size == 0)

return;

else {

int i;

for (i = 0; i < size; ++i) {

if (ob.equals(array[i]))

break;

}

if (i == size)

return;

Object e = array[i];

for (int x = i; x < this.array.length - 1; x++) {

array[x] = array[x + 1];

}

size--;

}

}

public int size() {

return size;

}

public boolean isEmpty() {

return size == 0;

}

public boolean contains(E ob) {

for (int i = 0; i < size; ++i) {

if (ob.equals(array[i]))

return true;

}

return false;

}

public int search(Object ob) {

for (int i = 0; i < size; ++i) {

if (ob.equals(array[i]))

return i;

}

return -1;

}

public String toString() {

String res = "";

for (int i = 0; i < size; ++i) {

res = res + array[i] + " ";

}

return res;

}

@Override

public boolean equals(Object other) {

if (other == null)

return false;

System.out.println(this);

System.out.println((Integer) other);

if (other == this)

return true;

return false;

}

public static void main(String args[]){

MyArrayList<String> myArrayList = new MyArrayList<String>();

myArrayList.add("Rahul");

myArrayList.add("Chegg");

System.out.println(myArrayList.toString());

System.out.println("Size of String arrayList is: " + myArrayList.size );

myArrayList.add("Hello");

System.out.println("Size of String arrayList is: " + myArrayList.size );

for(int i=0;i<myArrayList.size;++i){

System.out.print(myArrayList.array[i] + " ");

}

System.out.println("\n");

MyArrayList<Integer> myArrayList1 = new MyArrayList<Integer>();

myArrayList1.add(1);

myArrayList1.add(2);

System.out.println(myArrayList1.toString());

System.out.println("Size of Integer arrayList is: " + myArrayList1.size );

}

}

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