Skip to main content

Collection(Vector,Stack)

Vector:-Vector is a group of individual objects it is also called legacy class. Vector implements List Interface. Like ArrayList it also maintains insertion order but it is rarely used in non-thread environment as it is synchronized and due to which it gives poor performance in searching, adding, delete and update of its elements.

Three ways to create vector class object:

Method 1:-
Vector v = new Vector();
It creates an empty Vector with the default initial capacity of 10. It means the Vector will be re-sized when the 11th elements needs to be inserted into the Vector. Note: By default vector doubles its size. i.e. In this case the Vector size would remain 10 till 10 insertions and once we try to insert the 11th element It would become 20 (double of default capacity 10).
Method 2:
Syntax: Vector object= new Vector(int initialCapacity)
Vector v = new Vector(3);
It will create a Vector of initial capacity of 3.
Method 3:
Syntax:
Vector object= new vector(int initialcapacity, capacityIncrement)
Vector v= new Vector(4, 6)
Here we have provided two arguments. The initial capacity is 4 and capacityIncrement is 6. It means upon insertion of 5th element the size would be 10 (4+6) and on 11th insertion it would be 16(10+6).

Example1:-VectorExample.java

import java.util.*;
 
public class VectorExample {
 
   public static void main(String args[]) {
      Vector v = new Vector ();
 
      v.addElement("Apple");
      v.addElement("Orange");
      v.addElement("Mango");
      v.addElement("Fig");
 
      System.out.println("Size is: "+v.size());
      System.out.println("Default capacity increment is: "+v.capacity());
 
      v.addElement("fruit1");
      v.addElement("fruit2");
      v.addElement("fruit3");
 
      System.out.println("Size after addition: "+v.size());
      System.out.println("Capacity after increment is: "+v.capacity());
 
      Enumeration en = v.elements();
      System.out.println("\nElements are:");
      while(en.hasMoreElements())
         System.out.print(en.nextElement() + " ");
   }
}
Output:
Size is: 4
Default capacity increment is: 4
Size after addition: 7
Capacity after increment is: 8
 
Elements are:
Apple Orange Mango Fig fruit1 fruit2 fruit3
 

methods of Vector Class:

1.     void addElement(Object element): It inserts the element at the end of the Vector.
2.     int capacity(): This method returns the current capacity of the vector.
3.     int size(): It returns the current size of the vector.
4.     void setSize(int size): It changes the existing size with the specified size.
5.     boolean contains(Object element): This method checks whether the specified element is present in the Vector. If the element is been found it returns true else false.
6.     boolean containsAll(Collection c): It returns true if all the elements of collection c are present in the Vector.
7.     Object elementAt(int index): It returns the element present at the specified location in Vector.
8.     Object firstElement(): It is used for getting the first element of the vector.
9.     Object lastElement(): Returns the last element of the array.
10.    Object get(int index): Returns the element at the specified index.
11.    boolean isEmpty(): This method returns true if Vector doesn’t have any element.
12.    boolean removeElement(Object element): Removes the specifed element from vector.
13.    boolean removeAll(Collection c): It Removes all those elements from vector which are present in the Collection c.
14.    void setElementAt(Object element, int index): It updates the element of specifed index with the given element.
Stack:-Stack is a special designed class which is sub class of vector class where insertion and deletion perform from single end.
Methods of stack class are:-
public E push(E);
 public synchronized E pop();
 public synchronized E peek();
 public boolean empty();
 public synchronized int search(java.lang.Object);
Example1:-TestStack.java
import java.util.*;
class TestStack
{
public static void main(String[]args)
{
Stack s=new Stack();
s.push("A");
s.push("B");
s.push("C");
s.push("D");
System.out.println(s);
Iterator itr=s.iterator();
while(itr.hasNext())
{
System.out.println(itr.next());
}
System.out.println("poped element is :"+s.pop());
System.out.println(s);
System.out.println("peeked element is :"+s.pop());
System.out.println(s);
System.out.println(s.empty());
System.out.println(s.search("A"));
System.out.println(s.search("D"));
}
}
Output:-
C:\JAVATECH>javac TestStack.java
C:\JAVATECH>java TestStack
[A, B, C, D]
A
B
C
D
poped element is :D
[A, B, C]
peeked element is :C
[A, B]
false
2

-1

Labels:

Comments

Post a Comment

Popular posts from this blog

Inner classes

Inner Classes:- class inside class or interface called inner class or nested class. Advantage of inner classes is grouping multiple classes and interfaces into a single class. Another big advantage of inner class is that inner class can happily access all the data or variables of outer class directly. Types of Nested classes:- There are two types of nested classes static and non-static nested classes. (A)Non –static inner classes:- 1)     Member inner class 2)     Anonymous inner class 3)     Local inner class (B)Static nested class Example1:-Outer.java class Outer { class Inner { void disp() { System.out.println("Hello This is Inner class Method"); } } public static void main(String[]args) { Inner in=new Inner(); in.disp(); } } Output:- C:\JAVATECH>javac Outer.java Outer.java:12: error: non-static variable this cannot be referenced from a static context Inner in=new Inner(); ...
Post a Comment
Read more

Inheritance-4

Example10:- class Student { Student() { System.out.println("This is super class Zero argument constructor"); } Student(String s) { System.out.println("This is super class One argument constructor"); } } class Test extends Student { Test() { super(null); System.out.println("This is sub class Zero argument constructor"); } public static void main(String[]args) { Test t=new Test(); } } Output:- C:\JAVATECH>javac Test.java C:\JAVATECH>java Test This is super class One argument constructor This is sub class Zero argument constructor Example11:- class Student { Student() { System.out.println("This is super class Zero argument constructor"); } Student(String s) { System.out.println("This is super class One argument constructor"); } } class Test extends Student { Test() { super(); super(null); System.out.println("This is su...
Post a Comment
Read more

Small concept about OOPs

Some small concept about OOPs:- In many books and website write about OOPs concepts as hundred percent object oriented, pure object oriented and partial object oriented language. Hundred percent object oriented:- In the hundred percent object oriented movie hero is object, without object program is incomplete that means can not execute program without object. Without class and object programming or application development is not possible. Example of hundred percent object oriented language is  Smalltalk . Pure object oriented:- In the object oriented cinema obviously object is the hero. In pure object oriented language object having same importance but in this having some relax that is without creating object we can successfully execute our application. So in the object oriented programming without class we cannot create or run our application, class is must. Example of pure object oriented language is  Java . Partial object oriented:- In this type of la...
Post a Comment
Read more