Collection classes are specialized classes for data storage and retrieval.

These classes provide support for stacks, queues, lists, and hash tables. Most collection classes implement the same interfaces.

Create and manage group of related object , Then there are two way to handle this first is array and second one is collection array are most useful for fixed and strongly type object.

Collection provide more flexible to work with group of object, group of object can shrink and grow dynamically.

for some collection when we need to assign a key to object then put into collection and retrive data using key.

A collection is a class, so you must declare a new collection before you can add elements to that

  1. using System;
  2. using System.Collections.Generic;
  3. using System.Linq;
  4. using System.Text;
  5. using System.Threading.Tasks;

  7. namespace Collection
  8. {
  9. class Program
  10. {
  11. /*
  12. Collection classes are specialized classes for data storage and retrieval.
  13. * These classes provide support for stacks, queues, lists, and hash tables. Most collection classes implement the same interfaces.
  14. */
  15. //*************************** Simple Collection ***************************
  16. //create and manage group of related object , Then there are two way to handle this first is array and second one is collection
  17. // array are most useful for fixed and strongly type object .
  18. // Collection provide more flexible to work with group of object, group of object can shrink and grow dynamically
  19. // for some collection when we need to assign a key to object then put into collection and retrive data using key
  20. //A collection is a class, so you must declare a new collection before you can add elements to that
  21. static void Main(string[] args)
  22. {
  23. var sal = new List<string> { "I", "M", "collection" }; // anonymos
  24. sal.Add("Manu"); // add value
  25. sal.Add("Gupta");
  26. foreach (var a in sal)
  27. {
  28. // Iterate value from list
  29. Console.WriteLine("Data is " + a);
  30. }
  31. Cat cat = new Cat { Age = 10, Name = "Fluffy" }; { }
  32. List<Cat> cats = new List<Cat> // Generic (string and int) used for type safety and type casting
  33. {
  34. new Cat(){ Name = "US", Age=8 },
  35. new Cat(){ Name = "Delhi", Age=2 },
  36. new Cat(){ Name = "London", Age=14 }
  37. };
  38. Console.WriteLine("Generic is ...........");
  39. foreach (Cat c in cats)
  40. {
  41. Console.WriteLine("Generic is " + c);
  42. }
  43. var salint = new List<int>();// strongly type
  44. salint.Add(1);
  45. salint.Add(2);
  46. foreach (var b in salint)
  47. {
  48. Console.WriteLine("Data is " + b);
  49. }
  50. salint.Remove(0); // remove element from 0 index
  51. var obj = new List<string> { "Faizabad", "Patna", "Varanasi" };
  52. for (var index = 0; index < obj.Count;index++ )
  53. {
  54. Console.WriteLine("In for loop " +obj[index] );
  55. }
  56. var theGalaxies = new List<Galaxy> // Galaxy is class
  57. {
  58. new Galaxy { Name="Tadpole", MegaLightYears=400},
  59. new Galaxy { Name="Pinwheel", MegaLightYears=25},
  60. new Galaxy { Name="Milky Way", MegaLightYears=0},
  61. new Galaxy { Name="Andromeda", MegaLightYears=3}
  62. };
  63. foreach (Galaxy theGalaxy in theGalaxies)
  64. {
  65. Console.WriteLine(theGalaxy.Name + " " + theGalaxy.MegaLightYears);
  66. }
  67. Console.ReadKey(true);
  68. }
  69. class Cat
  70. {
  71. public int Age { get; set; }
  72. public string Name { get; set; }
  73. }
  74. public class Galaxy
  75. {
  76. public string Name { get; set; }
  77. public int MegaLightYears { get; set; }
  78. }