Article Categories
- All Categories
-
Data Structure
-
Networking
-
RDBMS
-
Operating System
-
Java
-
MS Excel
-
iOS
-
HTML
-
CSS
-
Android
-
Python
-
C Programming
-
C++
-
C#
-
MongoDB
-
MySQL
-
Javascript
-
PHP
-
Economics & Finance
Articles on Trending Technologies
Technical articles with clear explanations and examples
MySQL ORDER BY with different ordering for some of the values as descending and others ascending?
You can use the field() for this. Let us first create a table −mysql> create table DemoTable ( Value int ); Query OK, 0 rows affected (0.80 sec)Insert some records in the table using insert command −mysql> insert into DemoTable values(10); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable values(70); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(60); Query OK, 1 row affected (0.14 sec) mysql> insert into DemoTable values(56); Query OK, 1 row affected (0.12 sec) mysql> insert into DemoTable values(81); Query OK, 1 row affected (0.44 sec) mysql> ...
Read MoreWhat is difference between a pointer and reference parameter in C++?
PointersPointer variables are used to store the address of variable.SyntaxType *pointer;InitializationType *pointer; Pointer=variable name;ReferencesWhen a parameter is declared as reference, it becomes an alternative name for an existing parameter.SyntaxType &newname=existing name;InitializationType &pointer; Pointer=variable name;The main differences between pointers and reference parameters are −References are used to refer an existing variable in another name whereas pointers are used to store address of variable.References cannot have a null value assigned but pointer can.A reference variable can be referenced by pass by value whereas a pointer can be referenced by pass by reference.A reference must be initialized on declaration while it is not ...
Read MoreWhat is the effect of extern "C" in C++?
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 MoreHow to add empty border to JPanel in Java?
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 MoreJava Program to select the first item in JList
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 MoreIs there a difference between copy initialization and direct initialization in C++?
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 MoreHow to make JOptionPane to handle Yes, No and Closed buttons in Java?
For this, create JOptionPane.QUESTION_MESSAGE and with the user action display individual messages, for example −int res = JOptionPane.showOptionDialog(new JFrame(), "Do you like Cricket?", "Hobbies", JOptionPane.YES_NO_OPTION, JOptionPane.QUESTION_MESSAGE, null, new Object[] { "Yes", "No" }, JOptionPane.YES_OPTION); if (res == JOptionPane.YES_OPTION) { System.out.println("Selected Yes!"); }Above, we have displayed a message on console if the user will selects YES button. The following is an example to make JOptionPane to handle Yes, No and Closed buttons −Examplepackage my; import javax.swing.JFrame; import javax.swing.JOptionPane; public class SwingDemo { public static void main(String args[]) { int res = JOptionPane.showOptionDialog(new JFrame(), "Do you like ...
Read MoreCombining multiple rows into a comma delimited list in MySQL?
To combine multiple rows into a comma delimited list, use the GROUP_CONCAT() method. Let us first create a table −mysql> create table DemoTable ( Id int NOT NULL AUTO_INCREMENT PRIMARY KEY, Name varchar(30), Marks int ); Query OK, 0 rows affected (0.52 sec)Insert some records in the table using insert command −mysql> insert into DemoTable(Name, Marks) values('John', 67); Query OK, 1 row affected (0.25 sec) mysql> insert into DemoTable(Name, Marks) values('Carol', 69); Query OK, 1 row affected (0.18 sec) mysql> insert into DemoTable(Name, Marks) values('Sam', 69); Query OK, 1 row affected (0.12 sec) mysql> insert ...
Read MoreJava Program to set Selection Mode for JList only for single selection
To set single selection for JList, use DefaultListSelectionModel and set it to SINGLE_SELECTION:String values[]= { "One", "Two", "Three", "Four", "Five", "Six"}; JList list = new JList(values); list.setSelectionMode(DefaultListSelectionModel.SINGLE_SELECTION);The following is an example to set the selection mode for JList only for single selection: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 MoreWhen should I write the keyword 'inline' for a function/method in C++?
In C++, the inline keyword is used in different places. To create inline variables, or inline namespace, and as well as to create inline methods or functions.C++ inline function is powerful concept that is commonly used with classes. If a function is inline, the compiler places a copy of the code of that function at each point where the function is called at compile time.Any change to an inline function could require all clients of the function to be recompiled because compiler would need to replace all the code once again otherwise it will continue with old functionality.To inline a ...
Read More