Enum is a user-defined datatype in C++ that is used to assign names to integer values. For example, you can use an enum to represent the days of the week from 0 to 6, where 0 represents Sunday, 1 represents Monday, and so on. When you try to access a value of an enum, it will only return an integer value. In this article, we will learn how to convert an enum type variable to a string type variable in C++, so that we can easily display the enum value as a string. Example of Enum: enum color ... Read More

A. You can create a table in a database using the CREATE TABLE query.SyntaxCREATE TABLE table_name( column1 datatype, column2 datatype, column3 datatype, ..... columnN datatype, PRIMARY KEY( one or more columns ) );To create a table in a database using JDBC API you need to:Register the driver: Register the driver class using the registerDriver() method of the DriverManager class. Pass the driver class name to it, as parameter.Establish a connection: Connect ot the database using the getConnection() method of the DriverManager class. Passing URL (String), username (String), password (String) as parameters to it.Create Statement: Create a Statement object using the createStatement() ... Read More

A. You can drop/delete a database using the DROP DATABASE query.SyntaxDROP DATABASE DatabaseName;To drop a Database using JDBC API you need to:Register the driver: Register the driver class using the registerDriver() method of the DriverManager class. Pass the driver class name to it, as parameter.Establish a connection: Connect ot the database using the getConnection() method of the DriverManager class. Passing URL (String), username (String), password (String) as parameters to it.Create Statement: Create a Statement object using the createStatement() method of the Connection interface.Execute the Query: Execute the query using the execute() method of the Statement interface.ExampleThe show databases command gives ... Read More

In general, You can change the current database in MySQL using the USE query.SyntaxUse DatabaseName;To change the current database using JDBC API you need to:Register the driver: Register the driver class using the registerDriver() method of the DriverManager class. Pass the driver class name to it, as parameter.Establish a connection: Connect ot the database using the getConnection() method of the DriverManager class. Passing URL (String), username (String), password (String) as parameters to it.Create Statement: Create a Statement object using the createStatement() method of the Connection interface.Execute the Query: Execute the query using the execute() method of the Statement interface.ExampleFollowing JDBC ... Read More

A. In general, you can create a database using the CREATE DATABASE query.SyntaxCREATE DATABASE DatabaseName;To create a Database using JDBC API you need to:Register the driver: Register the driver class using the registerDriver() method of the DriverManager class. Pass the driver class name to it, as parameter.Establish a connection: Connect ot the database using the getConnection() method of the DriverManager class. Passing URL (String), username (String), password (String) as parameters to it.Create Statement: Create a Statement object using the createStatement() method of the Connection interface.Execute the Query: Execute the query using the execute() method of the Statement interface.Example:Following JDBC program ... Read More

To add elements to the ArrayBlockingQueue class, use the add() method.The syntax is as follows:boolean add(E ele)Here, ele is the element to be added to the queue.To work with ArrayBlockingQueue class, you need to import the following package:import java.util.concurrent.ArrayBlockingQueue;The following is an example to add elements in Java ArrayBlockingQueue class:Example Live Demoimport java.util.concurrent.ArrayBlockingQueue; public class Demo {    public static void main(String[] args) {       ArrayBlockingQueue q = new ArrayBlockingQueue(7);       q.add(100);       q.add(250);       q.add(300);       q.add(450);       q.add(550);       q.add(600);       q.add(700);   ... Read More

To return a shallow copy of the CopyOnWriteArrayList, use the clone() method.The syntax is as follows:public Object clone()To work with CopyOnWriteArrayList class, you need to import the following package:import java.util.concurrent.CopyOnWriteArrayList;The following is an example to implement CopyOnWriteArrayList class clone() method in Java:Example Live Demoimport java.util.concurrent.CopyOnWriteArrayList; public class Demo {    public static void main(String[] args) {       CopyOnWriteArrayList arrList = new CopyOnWriteArrayList();       arrList.add(30);       arrList.add(90);       arrList.add(80);       arrList.add(70);       arrList.add(90);       arrList.add(100);       arrList.add(120);       System.out.println("CopyOnWriteArrayList = " + arrList);       System.out.println("Cloned CopyOnWriteArrayList = " + arrList.clone());    } }OutputCopyOnWriteArrayList = [30, 90, 80, 70, 90, 100, 120] Cloned CopyOnWriteArrayList = [30, 90, 80, 70, 90, 100, 120]

The poll() method of the ArrayBlockingQueue class in Java retrieves and removes the head of this queue, or returns null if this queue is empty.The syntax is as follows:E poll()To work with ArrayBlockingQueue class, you need to import the following package:import java.util.concurrent.ArrayBlockingQueue;The following is an example to implement poll() method of Java ArrayBlockingQueue class:Example Live Demoimport java.util.concurrent.ArrayBlockingQueue; public class Demo {    public static void main(String[] args) throws InterruptedException {       ArrayBlockingQueue q = new ArrayBlockingQueue(10);       q.add(200);       q.add(310);         q.add(400);       q.add(450);       q.add(500);     ... Read More

The empty() method of the DoubleStream class in Java returns an empty sequential DoubleStream.The syntax is as follows:static DoubleStream empty()To use the DoubleStream class in Java, import the following package:import java.util.stream.DoubleStream;Let us create an empty DoubleStream:DoubleStream doubleStream = DoubleStream.empty();Now, let us check the number of elements in the stream. It will be 0, since the stream is set to empty:doubleStream.count()The following is an example to implement DoubleStream empty() method in Java:Example Live Demoimport java.util.stream.DoubleStream; public class Demo {    public static void main(String[] args) {       DoubleStream doubleStream = DoubleStream.empty();       System.out.println("Number of elements in the stream ... Read More

The toArray() method returns an array containing the elements of this stream.The syntax is as follows:double[] toArray()To use the DoubleStream class in Java, import the following package:import java.util.stream.DoubleStream;Create DoubleStream and add some elements:DoubleStream doubleStream = DoubleStream.of(20.7, 30.5, 45.9, 60.2, 75.9, 88.3, 95.2);Now, use the toArray() method to return an array with the stream elements:double[] myArr = doubleStream.toArray();The following is an example to implement DoubleStream toArray() method in Java:Example Live Demoimport java.util.*; import java.util.stream.DoubleStream; public class Demo {    public static void main(String[] args) {       DoubleStream doubleStream = DoubleStream.of(20.7, 30.5, 45.9, 60.2, 75.9, 88.3, 95.2);       double[] ... Read More