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Virtual functions calling from a constructor or destructor is dangerous and should be avoided whenever possible as the virtual function we call is called from the Base class and not from the derived class.The reason is that in C++ Super-classes are constructed before derived classes. So, in the following example, as B must be instantiated, before D is instantiated. When B's constructor is called, it's not D yet, so the virtual function table still has the entry for B's copy of s().Example Code Live Demo#include using namespace std; class B { public: B() { s(); } ... Read More
Before getting into example, we should know what is runOnUiThread() in android. Sometimes Main thread performs some heavy operations. if user wants to add some extra operations on UI, it will get load and provides ANR. Using runOnUiThread going to do back ground operations on worker thread and update the result on main thread.This example demonstrate about How do we use runOnUiThread in Android.Step 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. ... Read More
You can use NOT IN operator for the rows you do not want to delete. Following is the syntax −delete from yourTableName where yourColumnName NOT IN(‘yourValue1’, ‘yourValue2’, ‘yourValue3’, .........N);Let us first create a table −mysql> create table deleteAllRowsWithCondition -> ( -> Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, -> Name varchar(20) -> ); Query OK, 0 rows affected (0.84 sec)Following is the query to insert some records in the table using insert command −mysql> insert into deleteAllRowsWithCondition(Name) values('Larry'); Query OK, 1 row affected (0.14 sec) mysql> insert into deleteAllRowsWithCondition(Name) values('John'); Query OK, 1 row affected ... Read More
Following is our file:Path p = Paths.get("E:/input.txt"); FileStore file = Files.getFileStore(p);Now, check for the supported attributes one by one:FileAttributeView = file.supportsFileAttributeView(FileAttributeView.class) PosixFileAttributeView = file.supportsFileAttributeView(PosixFileAttributeView.class) BasicFileAttributeView = file.supportsFileAttributeView(BasicFileAttributeView.class)Exampleimport java.nio.file.FileStore; import java.nio.file.Files; import java.nio.file.Path; import java.nio.file.Paths; import java.nio.file.attribute.BasicFileAttributeView; import java.nio.file.attribute.FileAttributeView; import java.nio.file.attribute.FileOwnerAttributeView; import java.nio.file.attribute.PosixFileAttributeView; public class Demo { public static void main(String[] args) throws Exception { Path p = Paths.get("E:/input.txt"); FileStore file = Files.getFileStore(p); System.out.println("FileAttributeView = " + file.supportsFileAttributeView(FileAttributeView.class)); System.out.println("PosixFileAttributeView = "+ file.supportsFileAttributeView(PosixFileAttributeView.class)); System.out.println("BasicFileAttributeView = "+ file.supportsFileAttributeView(BasicFileAttributeView.class)); System.out.println("FileOwnerAttributeView supported = "+ file.supportsFileAttributeView(FileOwnerAttributeView.class)); ... Read More
You can use LPAD() from MySQL for this. Let us first create a table −mysql> create table DemoTable ( FullName varchar(100) ); Query OK, 0 rows affected (0.81 sec)Insert records in the table using insert command −mysql> insert into DemoTable values('John Smith'); Query OK, 1 row affected (0.22 sec) mysql> insert into DemoTable values('David Miller'); Query OK, 1 row affected (0.21 sec) mysql> insert into DemoTable values('Sam Williams'); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values('Carol Taylor'); Query OK, 1 row affected (0.47 sec)Display records from the table using select command −mysql> select *from DemoTable;This ... Read More
A read-only double buffer can be created using the contents of a buffer with the method asReadOnlyBuffer() in the class java.nio.DoubleBuffer. The new buffer cannot have any modifications as it is a read-only buffer. However, the capacity, positions, limits etc. of the new buffer are the same as the previous buffer.A program that demonstrates this is given as follows −Example Live Demoimport java.nio.*; import java.util.*; public class Demo { public static void main(String[] args) { int n = 5; try { DoubleBuffer buffer = DoubleBuffer.allocate(5); buffer.put(4.5D); ... Read More
This example demonstrate about How to create DigitalSpeedDashboard in android.Step 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 − Open build.gradle and add library dependency as shown below –apply plugin: 'com.android.application' android { compileSdkVersion 28 defaultConfig { applicationId "com.example.andy.myapplication" minSdkVersion 19 targetSdkVersion 28 versionCode 1 versionName "1.0" testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner" } configurations { cleanedAnnotations compile.exclude ... Read More
Before getting into example, we should know what sqlite data base in android is. SQLite is an open source SQL database that stores data to a text file on a device. Android comes in with built in SQLite database implementation. SQLite supports all the relational database features. In order to access this database, you don't need to establish any kind of connections for it like JDBC, ODBC etc.This example demonstrate about How to use hex () in Android sqliteStep 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create ... Read More
An immutable copy of a LocalDateTime where the required duration is subtracted from it can be obtained using the minus() method in the LocalDateTime class in Java. This method requires two parameters i.e. the duration to be subtracted and the TemporalUnit of the duration. Also, it returns the LocalDateTime object with the required duration subtracted from it.A program that demonstrates this is given as follows −Example Live Demoimport java.time.*; import java.time.temporal.*; public class Demo { public static void main(String[] args) { LocalDateTime ldt = LocalDateTime.now(); System.out.println("The LocalDateTime is: " + ldt); ... Read More
To create Decade Tuple from another collection in Java, use the fromArray() or the fromCollection() method. Here, we will see how to create a Decade Tuple using the fromCollection() method. This method will allow us to crate a Decade Tuple from a List collection in Java.Let us first see what we need to work with JavaTuples. To work with Decade class in JavaTuples, you need to import the following packageimport org.javatuples.Decade;Note Download JavaTuples Jar library to run JavaTuples program. If you are using Eclipse IDE, then RightClick Project -> Properties -> Java Build Path -> Add External Jars and upload ... Read More