/*

In arrays, one operation can only be applied at a time but it is not the case with vectors

Java.util.Vector Class in Java.

The Vector class implements a growable array of objects. Vectors basically falls in legacy classes but now it is fully compatible with

collections.

Vector implements a dynamic array that means it can grow or shrink as required. Like an array, it contains components that can be

accessed using an integer index

They are very similar to ArrayList but Vector is synchronised and have some legacy method which collection framework does not contain.

It extends AbstractList and implements List interfaces.

Constructor:

Vector(): Creates a default vector of initial capacity is 10.

Vector(int size): Creates a vector whose initial capacity is specified by size.

Vector(int size, int incr): Creates a vector whose initial capacity is specified by size and increment is specified by incr. It specifies

the number of elements to allocate each time that a vector is resized upward.

Vector(Collection c): Creates a vector that contains the elements of collection c.

Important points regarding Increment of vector capacity:

If increment is specified, Vector will expand according to it in each allocation cycle but if increment is not specified then vector’s

capacity get doubled in each allocation cycle. Vector defines three protected data member:

int capacityIncreament: Contains the increment value.

int elementCount: Number of elements currently in vector stored in it.

Object elementData[]: Array that holds the vector is stored in it.*/

package vector;

import java.util.*;

public class VectorDemo

{

public static void main(String args[])

{

Vector v=new Vector(3,2);

System.out.println("Initial Size"+v.size());

System.out.println(" Initial Size"+v.capacity());

v.addElement(new Integer(1)));

v.addElement(new Integer(2)));

v.addElement(new Integer(3)));

v.addElement(new Integer(4)));

System.out.println(" Capacity after adding four elements"+v.capacity());

v.addElement(new Double(5.45));

System.out.println(" current Capacity"+v.capacity());

v.addElement(new Double(6.05));

v.addElement(new Integer(7)));

System.out.println(" current Capacity"+v.capacity());

v.addElement(new Float(9.3)));

v.addElement(new Integer(10)));

System.out.println(" current Capacity"+v.capacity());

v.addElement(new Integer(11)));

v.addElement(new Integer(12)));

System.out.println(" First Element"+(Integer)v.firstElement());

System.out.println(" last element"+(Integer)v.lastElement());

if(v.contains(new Integer(3))){

System.out.println(" vector contains 3");

Enumeration vEnum=v.elements();

System.out.println(" \nElement is vector:");

while(vEnum.hasMoreElements())

{

System.out.println(vEnum.nextElement()+"");

System.out.println();

}}}

Output:

Initial Size:0

Initial Capacity:3

Capacity after four addition5

Current Capacity 5

Current Capacity 7

Current Capacity9

First Element1

last Element:12

vector contains 3.

Element is vector:

1

2

3

4

5.45

6.05

7

9.3

10

11

12