Write an abstract class using C #

Using System;

Using System.Collections.Generic;

Using System.ComponentModel;

Using System.Data;

Using System.Drawing;

Using System.Linq;

Using System.Text;

Using System.Windows.Forms;

Namespace WindowsFormsApplication4

{

public partial class Form1:form

{

Public Form1 ()

{

InitializeComponent ();

}

Interface IPlayer

{

String Play ();

String Stop ();

String Pause ();

String Pre ();//The first skeleton?

String Next ();

}

IPlayer IPlayer;

public class Mp3:iplayer

{

public string Play ()

{

Return "Positive y in ú broadcast ￥ put?" MP3 song è qu ú!? ";

}

public string Stop ()

{

Return "Stop 1 broadcast ￥ put?" MP3 song è qu ú!? ";

}

public string Pause ()

{

Return "Temporary y stop sowing ￥ to put?" MP3 song è qu ú!? ";

}

public string Pre ()

{

Return "broadcast ￥ put?" first 罬 P3 song è qu ú!? ";

}

public string Next ()

{

Return "Sow ￥ next?" First 罬 P3 song è qu ú!? ";

}

}

public class Avi:iplayer

{

public string Play ()

{

Return "Positive y in ú broadcast ￥ put?" Avi song è qu ú!? ";

}

public string Stop ()

{

Return "Stop 1 broadcast ￥ put?" Avi song è qu ú!? ";

}

public string Pause ()

{

Return "Temporary y stop sowing ￥ to put?" Avi song è qu ú!? ";

}

public string Pre ()

{

Return "broadcast ￥ put?" first 罙 vi song è qu ú!? ";

}

public string Next ()

{

Return "Sow ￥ next?" First 罙 vi song è qu ú!? ";

}

}

private void Button7_click (object sender, EventArgs e)

{

Avi avi = new avi ();

iplayer = (iplayer) avi;

}

private void Button3_Click (object sender, EventArgs e)

{

Label1. Text + = iplayer. Pause ();

}

private void Button1_Click (object sender, EventArgs e)

{

MP3 mp3 = new MP3 ();

iplayer = (iplayer) mp3;

}

private void Form1_Load (object sender, EventArgs e)

{

}

private void Label1_click (object sender, EventArgs e)

{

}

private void Button2_Click (object sender, EventArgs e)

{

Label1. Text + = iplayer. Pre ();

}

private void Button4_Click (object sender, EventArgs e)

{

Label1. Text + = iplayer. Play ();

}

private void Button5_click (object sender, EventArgs e)

{

Label1. Text + = iplayer. Pause ();

}

private void Button6_click (object sender, EventArgs e)

{

MP3 m = new MP3 ();

Label1. Text + = iplayer. Next ();

}

}

}

Write an abstract class using C #