does array implements IEnumerable?

Question

I know that the base abstract Array class doesn't implement generic IEnumerable as

public abstract class Array : ICloneable, IList, ICollection, IEnumerable, IStructuralComparable, IStructuralEquatable
{
 ...
}

so when I create a derive array class like int[] i; or string[] s;, do they implement IEnumerable<T>? And how can I see the source code of []?

Answer 1

You can check it simply like this:

var type = typeof(int[]); // or any other type
foreach (var @interface in type.GetInterfaces())
    Console.WriteLine(@interface);

Result is:

System.ICloneable
System.Collections.IList
System.Collections.ICollection
System.Collections.IEnumerable
System.Collections.IStructuralComparable
System.Collections.IStructuralEquatable
System.Collections.Generic.IList`1[System.Int32]
System.Collections.Generic.ICollection`1[System.Int32]
System.Collections.Generic.IEnumerable`1[System.Int32]
System.Collections.Generic.IReadOnlyList`1[System.Int32]
System.Collections.Generic.IReadOnlyCollection`1[System.Int32]

Answer 2

There is special type SZArrayHelper - wrapper around array. Here is source code: https://referencesource.microsoft.com/#mscorlib/system/array.cs,aa97964558672440

Also, array implements IList, and it implements ICollection and it implements IEnumerable. So, Array implements IEnumerable

Answer 3

Official word here

Array Overview

An array has the following properties:

• An array can be Single-Dimensional, Multidimensional or Jagged.

• The number of dimensions and the length of each dimension are established when the array instance is created. These values can't be changed during the lifetime of the instance.

• The default values of numeric array elements are set to zero, and reference elements are set to null.

• A jagged array is an array of arrays, and therefore its elements are reference types and are initialized to null.

• Arrays are zero indexed: an array with n elements is indexed from 0 to n-1.

• Array elements can be of any type, including an array type.

• Array types are reference types derived from the abstract base type Array. Since this type implements IEnumerable and IEnumerable<T>, you can use foreach iteration on all arrays in C#.