Dynamic_array.java

package Java_practice;

public class Dynamic_array {


        private int array[];
        private int count;
        private int sizeofarray;

        //creating a constructor of the class that initializes the values
        public Dynamic_array()
        {
            array = new int[1];
            count = 0;
            sizeofarray = 1;
        }
        //creating a function that appends an element at the end of the array
        public void addElement(int a)
        {
//compares if the number of elements is equal to the size of the array or not
            if (count == sizeofarray)
            {
//invoking the growSize() method that creates an array of double size
                growSize();
            }
//append an element at the end of the array
            array[count] = a;
            count++;
        }
        //function that creates an array of double size
        public void growSize()
        {
//declares a temp[] array
            int temp[] = null;
            if (count == sizeofarray)
            {
//initialize a double size array of array
                temp = new int[sizeofarray * 2];
                {
                    for (int i = 0; i < sizeofarray; i++)
                    {
//copies all the elements of the old array
                        temp[i] = array[i];
                    }
                }
            }
            array = temp;
            sizeofarray= sizeofarray * 2;
        }
        //creating a function that deletes an element at the specified index
        public void addElementAt(int index, int a)
        {
//compare the size with the number of elements if not equal grows the array size
            if (count == sizeofarray)
            {
//invoking growSize() method
                growSize();
            }
            for (int i = count - 1; i >= index; i--)
            {
//shifting all the elements to the left from the specified index
                array[i + 1] = array[i];
            }
//inserts an element at the specified index
            array[index] = a;
            count++;
        }
        public static void main(String[] args)
        {
            Dynamic_array da = new Dynamic_array();
//adding elements to the array
            da.addElement(12);
            da.addElement(22);
            da.addElement(35);
            da.addElement(47);
            da.addElement(85);
            da.addElement(26);
            da.addElement(70);
            da.addElement(81);
            da.addElement(96);
            da.addElement(54);
            System.out.println("Elements of the array:");
//iterate over the array for accessing the elements
            for (int i = 0; i < da.sizeofarray; i++)
            {
                System.out.print(da.array[i] + " ");
            }
            System.out.println();
//determines and prints the size and number of elements of the array
            System.out.println("Size of the array: " + da.sizeofarray);
            System.out.println("No. of elements in the array: " + da.count);
//invoking the method to add an element at the specified index
            da.addElementAt(5, 99); //where 5 is the index number and 99 is the element to be add
            System.out.println("\nElements of the array after adding an element at index 5:");
//iterate over the array for accessing the elements after adding the element at index 5
            for (int i = 0; i < da.sizeofarray; i++)
            {
                System.out.print(da.array[i] + " ");
            }
            System.out.println();
//determines and prints the size and number of elements of the array
            System.out.println("Size of the array: " + da.sizeofarray);
            System.out.println("No. of elements in the array: " + da.count);
        }
    }