Program Using 'Vector' class

The Vector class implements a growable array of objects. Like an array, it contains elements that can be accessed using an integer index. However, the size of a Vector can grow or shrink as needed to accommodate adding and removing items after the Vector has been created. It has methods such as capacity( ), size( ), addElement( ), copyInto( ), contains( ), etc.

Here in this program we are providing vector elements from command line arguments and store them in a vector v using addElement( ) method as shown in program. After that we have copied all the vector elements in String array and display them on console. The Vector class is present in java.util package. The syntax for creating a vector is shown below:
// Creates a vector with initial size 10
Vector  <vector-name> = new  Vector();
OR 
// Creates a vector with specified initial capacity.
Vector  <vector-name> = new  Vector(initialCapacity);
OR 
// Creates a vector with specified initial capacity and capacity increment.
Vector  <vector-name> = new  Vector(initialCapacity,  capacityIncrement);

PROGRAM
import java.util.Vector;

public class VectorDemo2 {

 public static void main(String[] args) {
  
  Vector v = new Vector();
  
  // Adding elements to vector
  v.addElement(new Integer(10));
  v.addElement(new String("ABC"));
  v.addElement(new Float(34.4));
  
  int size = v.size();
  System.out.println("Vector size : "+size);
  System.out.println(v);
  //Removing element from vector
  v.removeElementAt(2);
  size = v.size();
  System.out.println("Vector size : "+size);
  System.out.println(v);
 }

}
OUTPUT 
C:\>javac VectorDemo2.java
C:\>java VectorDemo2
Vector size : 3
[10, ABC, 34.4]
Vector size : 2
[10, ABC]

Popular posts from this blog

Program to define a class 'employee' with data members as empid, name and salary. Accept data for 5 objects using Array of objects and print it.

This program demonstrates you the array of objects.  Array of object  is the collection of objects of the same class. The given syntax will define an array of reference therefore assign object to individual reference in the array to declare the array of object. The syntax to define array of object is: <class-name> <array-name> [size]; For example, the following statement will define an array of object having size 6 references to the class  Box . Box b[6]; For creating an array of objects (allocating memory) you have to write down the following statements for (int i=0; i<6; i++) { b[i] = new Box(); // Assigning object to individual reference in the array. } PROGRAM import java.util.Scanner; public class Employee { int empid; String name; float salary; public void getInput() { Scanner in = new Scanner(System.in); System.out.print("Enter the empid :: "); empid = in.nextInt(); System.out.print("Enter the name :: ");
Read more

Define a class Student with four data members such as name, roll no.,sub1, and sub2. Define appropriate methods to initialize and display the values of data members. Also calculate total marks and percentage scored by student.

In this program, first we first create a class  Student  which have data members  name, roll_no, sub1, sub2  and one method to read data here  getdata( )  method and show the result here  show( )  method. We have used  java.io.BufferedReader  class to read data from keyboard at runtime. Then we have created an object of Student class in  StudentDemo  class and called the methods of Student class. When you compile the code using  javac StudentDemo.java  command two .class files will be created which are  Student.class  and  StudentDemo.class , this has the advantage that you can reuse your .class file somewhere in other projects without compiling the code again. You can create as many classes as you want but writing many classes in a single file is not recommended as it makes code difficult to read rather you can create single file for every class. You can also group classes in packages for easily managing your code. PROGRAM import java.lang.*; import java.io.*; class Student {
Read more

Program to input age from user and throw user-defined exception if entered age is negative

An  Exception  is an abnormal condition that arises in a code sequence at run time. Exceptions are run time errors. Exceptions generated by the Java are related to the fundamental errors that violate the Java language constraints. All exception classes are subtypes of the  java.lang.Exception  class. The exception class is a subclass of the  Throwable  class. Java defines several exception classes inside the standard package  java.lang . Some examples of exceptions are  ArithmeticException, ArrayIndexOutOfBoundsException, IndexOutOfBoundsException, NullPointerException, NumberFormatException, ClassNotFoundException,etc. When Java Interpreter caught an error such as divide by zero, the interpreter creates an exception object and throws it to inform that an error has occurred. Java has its own exception handling mechanism. It performs the following task: Find the problem –  Hit  the exception Inform that an error has occurred –  Throw  the exception Receives the error infor
Read more