Question

JAVA Programming

MagicSet. Write a class that represents a set. Recall that a set has the following properties it does not contain duplicates and order is not important. If you are unable to make a class that can use any type (generics), make your set handle whole numbers. You must implement your set using an array. The amount of storage used should grow and shrink as needed: it should be halved if the array is 25% full and doubled when full. Your set should support the following operations: a. Add a value b. Does the set contain a value c. Delete a value d. Union: return a new set containing all your values and another set e. toString Here is a UML diagram for a MagicSet that only handles whole numbers. Write a driver program to test your class.

Answer 1

class MagicSet

{

                int size;

                int[] arr;

               

                MagicSet()

                {

                                size = 0;

                                arr = new int[1];

                }

               

                MagicSet(MagicSet ob)

                {

                                this.size = ob.size;

                                arr = new int[ob.arr.length];

                               

                                int i;

                                for(i = 0; i < ob.arr.length; i++)

                                                this.arr[i] = ob.arr[i];

                }

               

                public boolean contains(int val)

                {

                                int i;

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

                                                if(arr[i] == val)

                                                                return true;

                                return false;

                }

               

                public void add(int val)

                {

                                if(contains(val))

                                                System.out.println(val + " is already present in the Set");

                                else

                                {

                                                if(arr.length == size)

                                                {

                                                                // create a new temporary array

                                                                int[] new_arr = new int[2 * size];

                                                                int i;

                                                               

                                                                // copy element of arr to temporary array

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

                                                                                new_arr[i] = arr[i];

                                                               

                                                                //add new value to array

                                                                new_arr[i] = val;

                                                               

                                                                // update array

                                                                arr = new_arr;

                                                }

                                                else

                                                                arr[size] = val;

                                               

                                                size++;

                                }

                }

               

                public int getIndex(int val)

                {

                                int i;

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

                                                if(arr[i] == val)

                                                                return i;

                                return -1;

                }

               

                public boolean delete(int val)

                {

                                // get index of val

                                int index = getIndex(val);

                               

                                // if element is not present in the set

                                if(index == -1)

                                                return false;

                               

                                // if element to be deleted is the last element

                                if(index == size - 1)

                                {

                                                // decrease the size of the set

                                                size--;

                                                if(4 * size <= arr.length)

                                                                reduceSize();

                                                return true;

                                }

                               

                                int i;

                                // shift all elements after val one position left

                                for(i = index + 1; i < size; i++)

                                                arr[i - 1] = arr[i];

                               

                                // decrease size of set

                                size--;

                               

                                if(4 * size <= arr.length)

                                                reduceSize();

                               

                                return true;

                }

               

                public void reduceSize()

                {

                                int len = arr.length/2;

                                int[] new_arr = new int[len];

                                int i;

                               

                                // copy element of arr to temporary array

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

                                                new_arr[i] = arr[i];

                               

                                // update array

                                arr = new_arr;

                }

               

                public MagicSet union(MagicSet ob)

                {

                                // create new MagicSet object

                                MagicSet ans = new MagicSet();

                               

                                ans.size = this.size + ob.size;

                               

                                ans.arr = new int[ans.size];

                               

                                int i;

                               

                                // copy elements of current object

                                for(i = 0; i < this.size; i++)

                                                ans.arr[i] = this.arr[i];

                               

                                // copy elements of object ob

                                for(i = 0; i < ob.size; i++)

                                                ans.arr[i + this.size] = ob.arr[i];

                               

                                return ans;

                }

               

                public String toString()

                {

                                String ans = "";

                                int i;

                               

                                ans += "Size of Set : " + size + "\nContents of set are ...\n";

                               

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

                                                ans += String.valueOf(arr[i] + "\n");

                               

                                return ans;

                }

               

                public static void main(String[] args)

                {

                                MagicSet ob1 = new MagicSet();

                               

                                //add elements to ob1

                                ob1.add(1);

                                ob1.add(2);

                                ob1.add(5);

                                ob1.add(4);

                                ob1.add(21);

                                ob1.add(14);

                               

                                System.out.println(ob1);

                               

                                // try to add already present object

                                ob1.add(4);

                               

                                if(ob1.delete(21))

                                                System.out.println("\n21 deleted");

                                else

                                                System.out.println("\n21 not present in the Set of not able to delete it");

                               

                                ob1.delete(1);

                                ob1.delete(5);

                                ob1.delete(14);

                                ob1.delete(21);

                                ob1.delete(4);

                               

                                System.out.println("\nAfter deleting 1, 5, 14, 21 ...\n" + ob1);

                               

                               

                                MagicSet ob2 = new MagicSet();

                               

                                //add elements to ob1

                                ob2.add(124);

                                ob2.add(24);

                                ob2.add(52);

                                ob2.add(40);

                               

                                System.out.println("\nFor ob2 ...\n" + ob2);

                               

                                MagicSet ob3 = ob1.union(ob2);

                               

                                System.out.println("\nFor ob3(union of ob1 and ob2) ...\n" + ob3);

                }

}

Sample Output :

C:AUsers\userDesktop javac MagicSet.java C:AUsers\userDesktop java MagicSet Size of Set : 6 Contents of set are 4 21 14 4 is already present in the Set 1 deleted After deleting 1. 5. 14. 21 Size of Set :1 Contents of set are For ob2 ..- Size of Set: 4 Contents of set are 124 24 52 40 For ob3 union of ob1 and ob2>) Size of Set :5 Contents of set are 124 24 52 40 C:XUsers user Desktop>