object keyword and defining fields like this in class

Question

User702049738 posted

Hello Experts;

Can you please help explain the following below

public class pode

{

   private object info;   // what does the object keyword mean. Does it mean an associated an instance of 

                                   //of an associated class, if so what instance class is it

    private pode after;  //why is the class used as a type for the after variable.

}

Answer 1

User-271186128 posted

Hi olybobo,

what does the object keyword mean.

It is the type of the field.

I suggest you could refer to the following code:

    public class Test1
    {
        //private: Access Modifiers
        //object: data type.
        //name: field name.
        private object name;
        
        //Test2: the data type is Test2. When you assign value to this field, the data type should be a Test2 type
        public Test2 T2;
 
    }

    public class Test2
    {
        public int ID { get; set; }
        public string Name { get; set; }
    }

       protected void Page_Load(object sender, EventArgs e)
        {
            Test2 t2 = new Test2() { ID = 1001, Name = "AAA" };

            Test1 t1 = new Test1();

            t1.T2 = t2; //

            Response.Write(t1.T2.Name);
        }

Best regards,
Dillion

Answer 2

User702049738 posted

Why is it exactly needed. Why is the object type needed in that manner. thank you.

Answer 3

User-434868552 posted

@olybobo

First, i suggest you complete the free Microsoft course "C# Fundamentals for Absolute Beginners" from the the Microsoft Virtual Academy https://mva.microsoft.com/en-US/training-courses/c-fundamentals-for-absolute-beginners-8295

Regarding your question:

public class pode
{
     private object info;
     private pode after;
}

olybobo, it is absolutely important that you study the following MSDN article:

https://msdn.microsoft.com/en-us/library/system.object(v=vs.110).aspx  "Object class" 

"System.Object is the ultimate base class of all classes in the .NET Framework; it is the root of the type hierarchy."

olybobo, object (i prefer to write System.Object) can represent any type the programmer desires.

objects, classes, and instances are fundamental building blocks of OOP (Object Oriented Programming)

Study this simple code snippet:

System.Object anything = null;
Console.WriteLine(anything);
Int32 ten = 10;
anything = ten;
Console.WriteLine(anything);
String olybobo = "olybobo";  // System.String is a class -- see MSDN
anything = olybobo;
Console.WriteLine(anything);
Boolean truth = true;
anything      = truth;
Console.WriteLine(anything);
DateTime dateTimeStructure = DateTime.Now; // DateTime is a struct -- see MSDN
anything = dateTimeStructure;
Console.WriteLine(anything);

output:

null
10
olybobo
True
2016-02-26 11:46:46

olybobo, where did you find the code that you have shown to us?  i'm guessing in a book or somewhere else because you would understand that code had you written it.

BTW, i'm not criticizing you; a c# beginner is someone who has started the very long journey to mastery of c# (i'm still learning myself).

BACK TO YOUR EXAMPLE:

the are types like Double, DateTime, String, et cetera

there are also custom types.

The class named poole in your example is a custom type.

poole contains 2  members:  info is an object; after is a poole.

The designer of the class poole would be able to tell you why she/he wanted the class poole to be able to contain an instance of itself.

study this example:

public class MyCustomType
{
    public MyCustomType myCustomType1;
    public MyCustomType myCustomType2;
}

void Main()
{
    MyCustomType myCustomType = new MyCustomType();
    myCustomType.myCustomType1 = null;
    myCustomType.myCustomType2 = null; 
    Console.WriteLine(myCustomType);
}

output:

MyCustomType

myCustomType1  null 

myCustomType2  null 

Answer 4

User702049738 posted

this is where i found the code. it was being used in implementing a linkedlist

https://www.youtube.com/watch?v=cEsicmlaWDk

Answer 5

User-434868552 posted

@olybobo

caution:  at the YouTube link, there is a follow up link to 

www  regawmod com ... Tutorial zip

McAfee's site advisor reports http://www.siteadvisor.com/sites/regawmod.com :

regawmod.com
This link is suspicious.
We tested it and found potential security risks. Be careful.

Website Category:
Parked Domain

YOUR  QUESTION ... 

Usually, there are features of the .NET Framework that meet most of our needs.

Sometimes we write code we do not need because we do not understand enough of the .NET Framework.

study https://msdn.microsoft.com/en-us/library/6sh2ey19(v=vs.110).aspx "List<T> Class"

Here is a trivial example using List<T>:

public class SharedBook
{
    public String Title;
    public DateTime DateBorrowed;
    public DateTime DateReturned;
    public String BorrowedBy;
}

The task is simply to write a list of borrowers and who had the book before and after each borrower.

void Main()
{
    List<SharedBook> sharedBooks = new List<SharedBook>();
    SharedBook borrower1 = new SharedBook { Title = "Animal Farm",
                    DateBorrowed = new DateTime(2014, 5, 15), DateReturned = new DateTime(2014, 6, 12),
                    BorrowedBy = "olyboro" };
    SharedBook borrower2 = new SharedBook { Title = "Animal Farm",
                    DateBorrowed = new DateTime(2014, 7, 17), DateReturned = new DateTime(2014, 7, 21),
                    BorrowedBy = "Terri" };
    SharedBook borrower3 = new SharedBook { Title = "Animal Farm",
                    DateBorrowed = new DateTime(2015, 1, 19), DateReturned = new DateTime(2015, 2, 2),
                    BorrowedBy = "Whoopi"
    };
    SharedBook borrower4 = new SharedBook { Title = "Animal Farm",
                    DateBorrowed = new DateTime(2016, 2, 21), DateReturned = new DateTime(2013, 2, 23),
                    BorrowedBy = "Cher"};
    sharedBooks.Add(borrower1);
    sharedBooks.Add(borrower2);
    sharedBooks.Add(borrower3);
    sharedBooks.Add(borrower4);
    // write our list ... there must be 3 or more books in the list for the following code to succeed
    String previous;
    String next;
    Int32  items = sharedBooks.Count;
    Console.WriteLine("     Title                  Previous       ------        Next");
    for (Int32 book = 0; book < items; book++)
    {
        if (book == 0) { previous = "*** in library ***"; next = sharedBooks[book + 1].BorrowedBy;}
        else if (book == items - 1) { previous = sharedBooks[book - 1].BorrowedBy; next = "*** not known ***";}
        else
        {
            previous = sharedBooks[book-1].BorrowedBy;
            next     = sharedBooks[book+1].BorrowedBy;
        }
        Console.WriteLine("{0}     {1}     {2}     {3}",
                            sharedBooks[book].Title,
                            previous,
                            sharedBooks[book].BorrowedBy,
                            next);
    }
}

output:

     Title                  Previous       ------        Next
Animal Farm     *** in library ***     olyboro     Terri
Animal Farm     olyboro     Terri     Whoopi
Animal Farm     Terri     Whoopi     Cher
Animal Farm     Whoopi     Cher     *** not known ***

 #########################################

olybobo, the code in the video that you mentioned is a special type of list.

BTW, you wrote    pode ...   node is the correct term.

STUDY these articles:

https://msdn.microsoft.com/en-us/library/he2s3bh7(v=vs.110).aspx "LinkedList<T> Class" "Represents a doubly linked list."

https://msdn.microsoft.com/en-us/library/ahf4c754(v=vs.110).aspx  "LinkedListNode<T> Class"
    "Represents a node in a LinkedList<T>. This class cannot be inherited."

http://www.dotnetperls.com/linkedlist 

 *

   * you do not need to read the article where i found the above image,
     however you can find it here:  
     http://www.codeofhonor.com/blog/avoiding-game-crashes-related-to-linked-lists

FWIW, olybobo, linked lists are a computer science topic; in day to day programming, most programmers will not be using linked lists.  Regardless, it is worth understanding how they work.

Answer 6

User702049738 posted

Thanks for the caution. I am going to remove the youtube link right now. thanks for the explanation.  I am just trying to learn and understand linkedlist from the C# perspective. I only modified it from a node to pode just for a better reflection and to fully understand why it was done in that manner....