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The extern “C” keyword is used to make a function name in C++ have the C linkage. In this case the compiler does not mangle the function. Let us see what is the mangling in C++ first, then we can discuss about the extern “C” keyword.In C++ we can use the function overloading feature. Using this feature, we can create functions with same name. The only difference is the type of the arguments, and the number of arguments. The return type is not considered here. Now the question comes how the C++ distinguishes overloaded functions in object code?In the object ... Read More
You can use remove() for this. Let us first create a collection with documents −> db.deleteDataDemo.insertOne({_id:1, "Name":"Larry"}); { "acknowledged" : true, "insertedId" : 1 } > db.deleteDataDemo.insertOne({_id:2, "Name":"Chris"}); { "acknowledged" : true, "insertedId" : 2 } > db.deleteDataDemo.insertOne({_id:3, "Name":"Robert"}); { "acknowledged" : true, "insertedId" : 3 } > db.deleteDataDemo.insertOne({_id:4, "Name":"David"}); { "acknowledged" : true, "insertedId" : 4 } > db.deleteDataDemo.insertOne({_id:5, "Name":"Carol"}); { "acknowledged" : true, "insertedId" : 5 } > db.deleteDataDemo.insertOne({_id:6, "Name":"Sam"}); { "acknowledged" : true, "insertedId" : 6 }Following is the query to display all documents from a collection with the help of find() method −> db.deleteDataDemo.find().pretty();This will produce ... Read More
To add empty border, use the createEmtyBorder() method. Let us first create a new JLabel −JLabel label; label = new JLabel("Label with empty border!");Now, set empty border using the setBorder() method −label.setBorder(BorderFactory.createEmptyBorder(10, 10, 10, 10));The following is an example to add empty border to JPanel −Examplepackage my; import javax.swing.BorderFactory; import java.awt.Font; import javax.swing.JFrame; import javax.swing.JLabel; public class SwingDemo { public static void main(String[] args) throws Exception { JFrame frame = new JFrame("Demo"); JLabel label; label = new JLabel("Label with empty border!"); label.setFont(new Font("Verdana", Font.PLAIN, 16)); ... Read More
To set multidimensional array into a table, we need the values for rows and columns. Therefore, create a multidimensional array for rows −Integer[][] marks = { { 70, 66, 76, 89, 67, 98 }, { 67, 89, 64, 78, 59, 78 }, { 68, 87, 71, 65, 87, 86 }, { 80, 56, 89, 98, 59, 56 }, { 75, 95, 90, 73, 57, 79 }, { 69, 49, 56, 78, 76, 77 } };Now, columns −String students[] = { "S1", "S2", "S3", "S4", "S5", "S6"};Add the rows and columns set above to the ... Read More
The $exists is used to check whethre a filed exists, whereas $ne is for not equal condition. Let us first create a collection with documents −> db.existsDemo.insertOne({"Name":"Chris", "Age":21}); { "acknowledged" : true, "insertedId" : ObjectId("5cd7c3916d78f205348bc650") } > db.existsDemo.insertOne({"Name":"", "Age":null}); { "acknowledged" : true, "insertedId" : ObjectId("5cd7c39a6d78f205348bc651") } > db.existsDemo.insertOne({"Name":null, "Age":24}); { "acknowledged" : true, "insertedId" : ObjectId("5cd7c3a66d78f205348bc652") } > db.existsDemo.insertOne({"Age":23}); { "acknowledged" : true, "insertedId" : ObjectId("5cd7c3c36d78f205348bc653") }Following is the query to display all documents from a collection with the help of find() method −> db.existsDemo.find().pretty();This will produce the following output −{ "_id" : ObjectId("5cd7c3916d78f205348bc650"), "Name" : "Chris", "Age" : 21 } { "_id" : ObjectId("5cd7c39a6d78f205348bc651"), "Name" : "", "Age" ... Read More
Removing duplicatesTo remove duplicates in an array we have many logical methods, but advanced javascript has provided some methods so that the task of removing duplicates has become very simple. Some of those methods are set() and filter(). For better understanding lets' discuss each method individually.Set()The important use of the set() method is that it only allows unique values. In other words, it will automatically remove duplicates and makes the task easy for us. The Set() method won't take any logical approach in removing duplicates.Example In the following example, the duplicates in the provided array have been removed without any ... Read More
Using loops in programming languages we can execute a set of statements repeatedly. Java provides various loops namely while loop, for loop and the do while loop.The for statement contains an initialization statement, a condition and, an increment or decrement operation.Initializing statement − The initialization determines the starting value of the loop.Condition − The condition in for loop is a statement returning a boolean value. This condition determines the exit value of the loop. It is executed before the statements of the loop.Increment and decrement − Using this the loop will be incremented or decremented to the next value.After initializing ... Read More
To select the first item in JList, use setSelectionInterval() method:String values[]= { "One", "Two", "Three", "Four", "Five", "Six"}; JList list = new JList(values); int begn = 0; int end = 0; list.setSelectionInterval(begn, end);The following is an example to select the first item in JList:Examplepackage my; import java.awt.event.*; import java.awt.*; import javax.swing.*; class SwingDemo extends JFrame { static JFrame frame; static JList list; public static void main(String[] args) { frame = new JFrame("JList Demo"); SwingDemo s = new SwingDemo(); JPanel panel = new JPanel(); String values[]= ... Read More
The Copy initialization can be done using the concept of copy constructor. As we know that the constructors are used to initialize the objects. We can create our copy constructor to make a copy of some other object, or in other words, initialize current object with the value of another object. On the other hand, the direct initialization can be done using assignment operation.The main difference between these two types of initialization is that the copy initialization creates a separate memory block for the new object. But the direct initialization does not make new memory space. It uses reference variable ... Read More
This example demonstrate about How to create a local Notifications in AndroidStep 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.Step 2 − Add the following code to res/layout/activity_main.xml. Step 3 − Add the following code to src/MainActivity.package app.tutorialspoint.com.notifyme ; import android.app.NotificationChannel ; import android.app.NotificationManager ; import android.os.Bundle ; import android.support.v4.app.NotificationCompat ; import android.support.v7.app.AppCompatActivity ; import android.view.View ; public class MainActivity extends AppCompatActivity { public static final String NOTIFICATION_CHANNEL_ID = "10001" ; private final static String default_notification_channel_id = "default" ... Read More