Commonly used wildcard characters are the asterisk (*). It represents zero or more characters in a string of characters.In the following example asterisk is used to match words that begins with m and ends with e −@”\bt\S*s\b”The following is the complete code −Example Live Demousing System; using System.Text.RegularExpressions; namespace Demo {    public class Program {       private static void showMatch(string text, string expr) {          MatchCollection mc = Regex.Matches(text, expr);          foreach (Match m in mc) {             Console.WriteLine(m);          }     ... Read More

Environment.Exit() methodThe Environment.Exit() method terminates the process and returns an exit code to the operating system −Environment.Exit(exitCode);Use exitCode as 0 (zero) to show that the process completed successfully.Use exitCode as a non-zero number to show an error, for example −Environment.Exit(1) − Return a value 1 to show that the file you want is not presentEnvironment.Exit(2) − Return a value 2 to indicate that the file is in an incorrect format.System.Windows.Forms.Application.ExitThread( )To close a subapplication or current thread in a Windows Form, use theSystem.Windows.Forms.Application.ExitThread( ).private void buttonClose_Click(object sender, EventArgs eventArgs) {    System.Windows.Forms.Application.ExitThread( ); }Read More

Firstly, set a list collection −List < string > myList = new List < string > (); myList.Add("RedHat"); myList.Add("Ubuntu");Now, use ToArray() to convert the list to an array −string[] str = myList.ToArray();The following is the complete code −Example Live Demousing System; using System.Collections.Generic; public class Program {    public static void Main() {       List < string > myList = new List < string > ();       myList.Add("RedHat");       myList.Add("Ubuntu");       Console.WriteLine("List...");       foreach(string value in myList) {          Console.WriteLine(value);       } ... Read More

Firstly, set the array −int[] p = new int[] {55, 66, 88, 99, 111, 122, 133};Now, let us say you need to set an element at position 1 −p[2] = 77;Let us see the comple code −Example Live Demousing System; namespace Program {    public class Demo {       public static void Main(string[] args) {          int[] p = new int[] {55, 66, 88, 99, 111, 122, 133};          int j;          Console.WriteLine("Initial Array......");          for (j = 0; j < p.Length; j++ ) { ... Read More

To swap characters of a string, use the Select method.Firstly, let’s say our string is −string str = "PQRQP";Now, you need to swap every occurrence of P with Q and Q with P −str.Select(a=> a == 'P' ? 'Q' : (a=='Q' ? 'P' : a)).ToArray();The above replaces the characters.Let us see the compelet code −Example Live Demousing System; using System.Linq; public class Program {    public static void Main() {       string str = "PQRQP";       var res= str.Select(a=> a == 'P' ? 'Q' : (a=='Q' ? 'P' : a)).ToArray();       str = new String(res);       Console.WriteLine(str);    } }OutputQPRPQ

To format a string, first set the value −int value = 55;Now to format the integer, use ToString and let’s say we need to set it for three places −value.ToString("000");The following is the complete code −Example Live Demousing System; public class Program {    public static void Main() {       int value = 55;       string res = value.ToString("000");       Console.WriteLine(res);    } }Output055

To add padding on the right to a string −const string format = "{0,10}";Now add it to the string −string str1 = string.Format(format, "Marks","Subject");Let us see the complete code −Example Live Demousing System; public class Program {    public static void Main() {       // set right padding       const string format = "{0,10}";       string str1 = string.Format(format, "Marks","Subject");       string str2 = string.Format(format, "95","Maths");       Console.WriteLine(str1);       Console.WriteLine(str2);    } }OutputMarks 95

Use the String.Fornt to format a string using %.String.Format format controls in C# also includes percentage (%) This multiplies the value by 100 and appends a percentage sign.Let’s say our value is −double val = .322;Now, use String.Format and format −string.Format("string = {0:0.0%}", val);The following is an example −Example Live Demousing System; public class Program {    public static void Main() {       double val = .322;       string res = string.Format("string = {0:0.0%}", val);       Console.WriteLine(res);    } }Outputstring = 32.2%

With C#, you can easily format content and add padding to it.To add padding −const string format = "{0,-5} {1,5}";Now, add the padding to the strings −string str1 = string.Format(format, "Rank","Student"); string str2 = string.Format(format, "2","Tom");Let us see the complete code −Example Live Demousing System; using System.Collections.Generic; public class Program {    public static void Main() {       // set padding       const string format = "{0,-5} {1,5}";       string str1 = string.Format(format, "Rank","Student");       string str2 = string.Format(format, "2","Tom");       Console.WriteLine(str1);       Console.WriteLine(str2);    } }OutputRank Student 2 Tom

Let’s say our string is −var str = "welcome";Use the substring() method and the following, if you want to rotate only some characters. Here, we are rotating only 2 characters −var res = str.Substring(1, str.Length - 1) + str.Substring(0, 2);The following is the complete code −Example Live Demousing System; public class Program {    public static void Main() {       var str = "welcome";       Console.WriteLine("Original String = "+str);       var res = str.Substring(1, str.Length - 1) + str.Substring(0, 2);       Console.WriteLine("Rotating two characters in the String: "+res);    } }OutputOriginal String = welcome Rotating two characters in the String: elcomewe