To initialize a string to an empty list −string myStr = null;Now, use the built-in method IsNullOrEmpty() to check whether the list is empty or not −if (string.IsNullOrEmpty(myStr)) {    Console.WriteLine("String is empty or null!"); }Let us see the complete code −Example Live Demousing System; namespace Demo {    class ... Read More

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 ... Read More

Let’s say we need to find that the following string is Palindrome or not −str = "Level";For that, convert the string into character array to chec each character −char[] ch = str.ToCharArray();Now find the reverse −Array.Reverse(ch);Use the Equals method to find whether the reverse is equal to original array or ... Read More

Use the ArrayList.Synchronized Method in C# for synchronization of ArrayList in C#.Let us see an example to lock the collection using SyncRoot property in C# −ArrayList arr = new ArrayList(); lock(arr.SyncRoot) {    foreach (object ele in arr) {    } }The following is the complete example to check the ... Read More

Firstly, set an array −int[] arr = {    87,    55,    23,    87,    45,    23,    98 };Now declare a dictionary and loop through the array and get the count of all the elements. The value you get from the dictionary displays the occurrence of ... Read More

Firstly, create an instance of DriveInfo −DriveInfo dInfo = new DriveInfo("E");Display free space −Console.WriteLine("Disk Free space = {0}", dInfo.AvailableFreeSpace); Now, use AvailableFreeSpace property and get the percentage of free space −Double pc = (dInfo.AvailableFreeSpace / (float)dInfo.TotalSize) * 100;Here, you will get the percentage of free size in comparison with the ... Read More

Firstly, set a jagged array.int[][] arr = new int[][] {    new int[] {       0,       0    }, new int[] {       1,       2    },    new int[] {       2,       4   ... Read More

In C#, use readonly to declare a const array.public static readonly string[] a = { "Car", "Motorbike", "Cab" };In readonly, you can set the value at runtime as well unlike const.Another alternative of achieving what we saw above −public ReadOnlyCollection a { get { return new List { "Car", "Motorbike", ... Read More

Use the Replace() method to replace a character with asterisks.Let’s say our string is −string str = "dem* text";To replace it, use the Replace() method −str.Replace('*', 'o');Here is the complete code −Example Live Demousing System; public class Program {    public static void Main() {       string str = ... Read More

Firstly, declare and initialize a jagged array.int[][] arr = new int[][] { new int[] {    0,    0 }, new int[] {    1,    2 }, new int[] {    2,    4 }, new int[] {    3,    6 }, new int[] {    4,   ... Read More