C# Class implementation with generics - c#-4.0

Question

Hi everyone I am studying C# but ran into some compiler errors:
I am getting the error: 'LinkedList' does not implement interface member 'IEnumerable.GetEnumerator()'
I think I did.
Below is the code:
using System;
using System.Collections.Generic;
namespace LinkedListGenericsExample
{
public class LinkedListNode<T>
{
//constructor
public LinkedListNode(T value)
{
//code here
}
//code here
}
//LinkedList class with generics. It inherit the IEnumerable class with
//generics. Should I use IEnumerable or IEnumerable<T>?
public class LinkedList<T>: IEnumerable<T>
{
//code here
}
public LinkedListNode<T> AddLast(T node)
{
//code here
}
public IEnumerator<T> GetEnumerator()
{
//code here
}
//here I think the GetEnumerator() method is implemented
IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
//Trying this but not working. Also I am confused.
/*
IEnumerator IEnumerable<T>.GetEnumerator()
{
return GetEnumerator();
}
*/
//Main() below
}
I am using the Visual Studio Code to compile the code.
Error ecountered:
'LinkedList' does not implement interface member 'IEnumerable.GetEnumerator()'
Using the generic type 'IEnumerator' requires 1 type arguments
Using the generic type 'IEnumerable' requreis 1 type arguments
'IEnumerable' in explicit interface declaration is not an interface
Question:
1) Should I inherit the IEnumerable class or IEnumerable class with generic?
2) How can I implement the "IEnumerable.GetEnumerator()" It looks like the compiler is not recognized my GetEnumerator() implementation but I am not sure why....
Need some help here. Thank you!
Updating the complete code below. It works!!
using System;
using System.Collections; //using System.Collections instead
namespace LinkedListGenericsExample
{
//Linked list node class in Generics form
public class LinkedListNode<T>
{
//LinkedListNode constructor
public LinkedListNode(T value)
{
this.Value = value;
}
public T Value;
public LinkedListNode<T> Next {get; internal set;}
public LinkedListNode<T> Prev {get; internal set;}
}
public class LinkedList<T>: IEnumerable
{
public LinkedListNode<T> First {get; private set;}
public LinkedListNode<T> Last {get; private set;}
public LinkedListNode<T> AddLast(T node)
{
var newNode = new LinkedListNode<T>(node);
if (First == null)
{
First = newNode;
Last = First;
}
else
{
Last.Next = newNode;
Last = newNode;
}
return newNode;
}
public IEnumerator GetEnumerator()
{
LinkedListNode<T> current = First;
while(current != null)
{
yield return current.Value;
current = current.Next;
}
}
IEnumerator IEnumerable.GetEnumerator()
{
return GetEnumerator();
}
/*
IEnumerator IEnumerable<T>.GetEnumerator()
{
}
*/
}
class Program
{
static void Main(string[] args)
{
//Console.WriteLine("Hello World!");
var list2 = new LinkedList<int>();
var list3 = new LinkedList<String>();
list2.AddLast(1);
list2.AddLast(3);
list2.AddLast(5);
//Go throuhg entire list of numbers
foreach(int i in list2)
{
Console.WriteLine(i);
}
Console.WriteLine();
list3.AddLast("2");
list3.AddLast("four");
list3.AddLast("foo");
//Go through entire list of strings
foreach(string s in list3)
{
Console.WriteLine(s);
}
}
}
}

Answer 1

Regarding your two questions, here are 2 cents.
1. I would suggest you implement the generic version. This would ensure type-safety and other benefits. You can read more on advantages of generics in this link. . Since you are learning C#, it would be a good idea to read about it.
Your implementation looks good.Please add reference to System.Collections namespace to your code for fixing the compile errors.
using System.Collections;