Vector Example program

Java Vector Class

• Java Vector class comes under the java.util package. The vector class implements a growable array of objects. Like an array, it contains the component that can be accessed using an integer index.

• Vector is very useful if we don't know the size of an array in advance or we need one that can change the size over the lifetime of a program.

• Vector implements a dynamic array that means it can grow or shrink as required. It is similar to the ArrayList, but with two differences-

• Vector is synchronized.
• The vector contains many legacy methods that are not the part of a collections framework

Three ways to create vector class object:

1.Vector vec=new Vector()

Method 2:
Syntax: Vector object= new Vector(int initialCapacity)




Method 3:




Vector object= new vector(int initialcapacity, capacityIncrement)

Example program :

import java.util.*;  
public class VectorExample1 {  
       public static void main(String args[]) {  
          //Create an empty vector with initial capacity 4  
          Vector<String> vec = new Vector<String>(4);  
          //Adding elements to a vector  
          vec.add("Tiger");  
          vec.add("Lion");  
          vec.add("Dog");  
          vec.add("Elephant");  
          //Check size and capacity  
          System.out.println("Size is: "+vec.size());  
          System.out.println("Default capacity is: "+vec.capacity());  
          //Display Vector elements  
          System.out.println("Vector element is: "+vec);  
          vec.addElement("Rat");  
          vec.addElement("Cat");  
          vec.addElement("Deer");  
          //Again check size and capacity after two insertions  
          System.out.println("Size after addition: "+vec.size());  
          System.out.println("Capacity after addition is: "+vec.capacity());  
          //Display Vector elements again  
          System.out.println("Elements are: "+vec);  
          //Checking if Tiger is present or not in this vector         
            if(vec.contains("Tiger"))  
            {  
               System.out.println("Tiger is present at the index " +vec.indexOf("Tiger"));  
            }  
            else  
            {  
               System.out.println("Tiger is not present in the list.");  
            }  
            //Get the first element  
          System.out.println("The first animal of the vector is = "+vec.firstElement());   
          //Get the last element  
          System.out.println("The last animal of the vector is = "+vec.lastElement());   
       }  
}