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Use the new keyword to instantiate a delegate. When creating a delegate, the argument passed to the new expression is written similar to a method call, but without the arguments to the method.For example −public delegate void printString(string s); printString ps1 = new printString(WriteToScreen);You can also instantiate a delegate using an anonymous method −//declare delegate void Del(string str); Del d = delegate(string name) { Console.WriteLine("Notification received for: {0}", name); };Let us see an example that declare and instantiates a delegate −Example Live Demousing System; delegate int NumberChanger(int n); namespace DelegateAppl { class TestDelegate { ... Read More
By using the WHERE clause with a DISTINCT clause in MySQL queries, we are putting a condition on the basis of which MySQL returns the unique rows of the result set. By using the LIMIT clause with a DISTINCT clause in MySQL queries, we are actually providing a perimeter to the server about a maximum number of unique rows of the result set to be returned.ExampleWe can use WHERE and LIMIT clause with DISTINCT as follows on the table named ‘testing’ −mysql> Select * from testing; +------+---------+---------+ | id | fname | Lname | +------+---------+---------+ | 200 ... Read More
For getting the records from MySQL table in the result set in a particular way either ascending or descending, we need to use the ORDER BY clause along with ASC or DESC keywords. If we will not use any of the above-mentioned keywords then MySQL by default return the records in ascending order. The ORDER BY clause returned the result set based on a particular field (ascending or descending order) with which we will use the ORDER BY clause. Suppose we want to sort the rows of the following table −mysql> Select * from Student; +--------+--------+--------+ | Name | ... Read More
Set the string −string str = "Cookie and Session";Use the following Regex to get the last 2 characters from string −Regex.Match(str,@"(.{2})\s*$")The following is the code −Example Live Demousing System; using System.Text.RegularExpressions; public class Demo { public static void Main() { string str = "Cookie and Session"; Console.WriteLine(Regex.Match(str,@"(.{2})\s*$")); } }Outputon
To join two lists, use AddRange() method.Set the first list −var list1 = new List < string > (); list1.Add("Keyboard"); list1.Add("Mouse");Set the second list −var list2 = new List < string > (); list2.Add("Hard Disk"); list2.Add("Pen Drive");To concatenate both the lists −lists1.AddRange(lists2);The following is the complete code −Exampleusing System.Collections.Generic; using System; namespace Demo { public static class Program { public static void Main() { var list1 = new List < string > (); list1.Add("Keyboard"); list1.Add("Mouse"); Console.WriteLine("Our list1...."); ... Read More
As we know that in MySQL we use the delimiter semicolon (;) to end each statement. The semicolon is the by default delimiter in MySQL. We need to change the delimiter, while creating a trigger, to tell MySQL that this is not the end of our trigger statement because we can use multiple statements in the trigger. We can change the delimiter temporarily by DELIMITER // statement to change the delimiter from Semicolon (;) to two back-slash (//). After this MySQL would know that the triggering statement only ends when it encounters a two back-slash (//). Following is an example ... Read More
To insert an item in an already created ArrayList, use the Insert() method.Firstly, set elements −ArrayList arr = new ArrayList(); arr.Add(45); arr.Add(78); arr.Add(33);Now, let’s say you need to insert an item at 2nd position. For that, use the Insert() method −// inserting element at 2nd position arr.Insert(1, 90);Let us see the complete example −Example Live Demousing System; using System.Collections; namespace Demo { public class Program { public static void Main(string[] args) { ArrayList arr = new ArrayList(); arr.Add(45); arr.Add(78); ... Read More
With the help of following MySQL command, we can check the tables of a database other than the database we are currently using −Show Tables from Database_name;For example, the following query would display the list of tables from a database named ‘gaurav’ when currently we are using a database named ‘new’ −mysql> use new; Database changed mysql> show tables from gaurav; +--------------------+ | Tables_in_tutorial | +--------------------+ | testing | | employee | | tender | | Ratelist | +--------------------+ 4 rows in set (0.00 sec)
Use the new operator to instantiate a class in C#.Let’s say our class is Line. Instantiation will create a new object as shown below −Line line = new Line();Using the object, you can now call the method −line.setLength(6.0);Let us see the example −Example Live Demousing System; namespace LineApplication { class Line { private double length; // Length of a line public Line() { Console.WriteLine("Object is being created"); } public void setLength( double len ) { length = len; ... Read More
C# has no built-in Math type. For the same, use a Dictionary.Firstly, create a Dictionary −Dictionary d = new Dictionary(); d.Add("keyboard", 1); d.Add("mouse", 2);Get the keys −var val = d.Keys.ToList();Now, use the foreach loop to iterate over the Map −foreach (var key in val) { Console.WriteLine(key); }To iterate it, try to run the following code −Example Live Demousing System; using System.Collections.Generic; using System.Linq; class Program { static void Main() { Dictionary d = new Dictionary(); d.Add("keyboard", 1); d.Add("mouse", 2); // get keys ... Read More