does not implement inherited abstract class

Question

3.00/5 (2 votes)

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OK. So I got a program handling books and movies. Now I have 1 base class, and 2 that inherit from that.

When I try to run it I get "does not implement inherited abstract member"

baseclass:

C#

public abstract class saker
   {
       public string titel;
       public string genre;
       public int pris;
       public abstract string book(string t, string g, int p, int page);
       public abstract string movie(string t, string g, int p, double l);
       public abstract string visainfo();
   }

class film:

C#

class  film : saker
  {
          double langd;
          public override string movie(string t, string g, int p, double l)
          {
              this.langd = l;
              this.titel = t;
              this.genre = g;
              this.pris = p;
          }
          public override string visainfo()
          {
              string s;
              s = "Titel: " + titel + " Genre: " + genre + " Pris: " + pris + "kr Langd: " + langd;
              return s;
          }
  }

Now what am I doing wrong?

[Edit - Answer from OP moved here - Henry]
ahh no its there, i just forgot to add the code snippet

C#

public class bok : saker
{
    int sidor;
    public override string book(string t, string g, int p, int page)
    {
        this.sidor = page;
        this.titel = t;
        this.genre = g;
        this.pris = p;
    }
    public override string visainfo()
    {
        string s;
        s = &quot;Titel: &quot; + titel + &quot; Genre: &quot; + genre + &quot; Pris: &quot; + pris + &quot;kr Sidor: &quot; + sidor;
        return s;
    }
}

[/Edit]

Posted 9-Feb-11 6:29am

splyez

Updated 16-Apr-18 21:33pm

Henry Minute

v3

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4 solutions

Solution 6

right click on base class (after :) while deriving into derived class and then select implement, then it will create dummy method[s] in derived class according to your abstract class methods signatures.

Posted 16-Apr-18 21:34pm

NAGI SETTY A

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Nish Nishant · Accepted Answer · 2011-02-09T06:33:00

Solution 1

You missed book, that needs to be implemented too.

Based on your updated question, you cannot implement the abstract methods over multiple classes where no single class implements all of them. That's not how it works. Every derived class needs to implement all the abstract methods from the base class.

Posted 9-Feb-11 6:33am

Nish Nishant

Updated 9-Feb-11 6:50am

v2

Comments

Sergey Alexandrovich Kryukov 9-Feb-11 12:49pm

My 5. Borrowed a book -- don't forget to put back!
--SA

Nish Nishant 9-Feb-11 12:50pm

:-)

Sandeep Mewara 9-Feb-11 12:52pm

Yep! Right. 5!

Henry Minute · Accepted Answer · 2011-02-09T06:42:00

Solution 3

Your saker class has three abstract members. You have to implement all three in each descendant.

So your Movie class must implement Book as well as Movie and your Book class must implement Movie as well as Book.

It looks like you need to redesign your saker class.

Posted 9-Feb-11 6:42am

Henry Minute

Comments

splyez 9-Feb-11 12:43pm

i c, ill look into that, yeah im not sure this is the way to go but

Nish Nishant 9-Feb-11 12:44pm

Voted 5, Henry. Good explanation.

Sergey Alexandrovich Kryukov 9-Feb-11 12:48pm

Yes, tell them "you have to!". My 5.
--SA

Sandeep Mewara 9-Feb-11 12:51pm

Simple and straight! 5!

Smitha Nishant · Accepted Answer · 2011-02-09T06:48:00

Here's an alternate design suggestion:

C#

public interface IBook
{
    string book(string t, string g, int p, int page);
}
interface IMovie
{
    string movie(string t, string g, int p, double l);
}
public abstract class saker
{
    public string titel;
    public string genre;
    public int pris;
    public abstract string visainfo();
}
public class Book : saker, IBook
{
    public override string visainfo()
    {
        throw new NotImplementedException();
    }
    public string book(string t, string g, int p, int page)
    {
        throw new NotImplementedException();
    }
}
public class Movie : saker, IMovie
{
    public override string visainfo()
    {
        throw new NotImplementedException();
    }
    public string movie(string t, string g, int p, double l)
    {
        throw new NotImplementedException();
    }
}