The list class has the function of a hash table

Using System;

Namespace Study
{
<summary>
Summary description of the Cchain.
</summary>
public class Cchain
{

public class Cchainnode
{
public object Data;
Public Cchainnode Nextchainnode;
Public Cchainnode Previouschainnode;
public object Tag;
public string Key;

Public Cchainnode ()
{
This. Data=null;
This. Tag=null;
This. Key=null;
This. Nextchainnode=this. Previouschainnode=null;
}

Public Cchainnode (Object Vdata,object vtag,string vkey)
{
This. Data=vdata;
This. Tag=vtag;
This. Key=vkey;
This. Nextchainnode=this. Previouschainnode=null;
}
}


public class Cchainiterator
{
Private Cchainnode Pcurrentchainnode,pfirstchainnode,plastchainnode;
private bool Pbfirst,pblast;

Public Cchainiterator (Cchainnode vfirstchainnode,cchainnode vlastchainnode)
{
This.pcurrentchainnode=this.pfirstchainnode=this.plastchainnode=null;
if (vfirstchainnode!=null)
{
Pcurrentchainnode=pfirstchainnode=vfirstchainnode;
Pbfirst=false;
}
if (vlastchainnode!=null)
{
Pcurrentchainnode=plastchainnode=vlastchainnode;
Pblast=false;
}
}

Public Cchainnode Currentchainnode
{
Get
{
return this.pcurrentchainnode;
}
}

public bool Nextchainnode ()
{
if (this.pfirstchainnode==null)
{
return false;
}
if (Pcurrentchainnode==pfirstchainnode && pbfirst==false)
{
Pbfirst=true;
return true;
}
Else
{
Pcurrentchainnode=pcurrentchainnode.nextchainnode;
if (Pcurrentchainnode ==null)
{
return false;
}
Else
{
return true;
}
}
}

public bool Previouschainnode ()
{
if (this.plastchainnode==null)
{
return false;
}
if (Pcurrentchainnode==plastchainnode && pblast==false)
{
Pblast=true;
return true;
}
Else
{
Pcurrentchainnode=pcurrentchainnode.previouschainnode;
if (Pcurrentchainnode ==null)
{
return false;
}
Else
{
return true;
}
}
}
}


Public Cchainnode Firstchainnode;
Public Cchainnode Lastchainnode;
Public Cchainnode Currentchainnode;

Public Cchain ()
{
This. Firstchainnode=this. Lastchainnode=this. Currentchainnode =null;
}

~cchain ()
{

}

public bool IsEmpty ()
{
if (this. Firstchainnode==null)
{
return true;
}
Else
{
return false;
}
}

public bool Appendchainnode (Cchainnode Vchainnode)
{

if (vchainnode==null)
{
return false;
}
Else
{
if (this. Firstchainnode==null)
{
This. Firstchainnode=vchainnode;
This. Firstchainnode.previouschainnode=null;
This. Firstchainnode.nextchainnode=null;
This. Lastchainnode=this. Currentchainnode=this. Firstchainnode;
}
Else
{
This. Currentchainnode.nextchainnode=vchainnode;
Vchainnode.previouschainnode=this. Currentchainnode;
Vchainnode.nextchainnode=null;
This. Lastchainnode=this. Currentchainnode=vchainnode;
}
return true;
}
}

public bool Insertchainnode (int index,cchainnode vchainnode)
{
Cchainnode PCn;
int pcount=0;
Cchain.cchainiterator pci=new Cchainiterator (this. Firstchainnode,null);
if (Vchainnode==null | | INDEX&LT;0)
{
return false;
}
if (index==0)
{
Pcn=this. Firstchainnode;
VCHAINNODE.NEXTCHAINNODE=PCN;
Pcn.previouschainnode=vchainnode;
This. Firstchainnode=vchainnode;
Vchainnode.previouschainnode=null;
return true;
}
while (Pci.nextchainnode () ==true)
{
pcount++;
if (Pcount==index)
{
Pcn=pci.currentchainnode.nextchainnode;
Pci.currentchainnode.nextchainnode=vchainnode;
Vchainnode.previouschainnode=pci.currentchainnode;
VCHAINNODE.NEXTCHAINNODE=PCN;
if (pcn!=null)
{
Pcn.previouschainnode=vchainnode;
}
return true;
}
}
return false;
}

public bool ContainsKey (string vkey)
{
Cchain.cchainiterator pci=new Cchainiterator (this. Firstchainnode,null);
while (Pci.nextchainnode () ==true)
{
if (PCi.CurrentChainNode.Key ==vkey)
{
return true;
}
}
return false;
}

Public Cchain.cchainnode Item (string vkey)
{
Cchain.cchainiterator pci=new Cchainiterator (this. Firstchainnode,null);
while (Pci.nextchainnode () ==true)
{
if (PCi.CurrentChainNode.Key ==vkey)
{
return pci.currentchainnode;
}
}
return null;
}

public Object ItemData (string vkey)
{
Cchain.cchainiterator pci=new Cchainiterator (this. Firstchainnode,null);
while (Pci.nextchainnode () ==true)
{
if (PCi.CurrentChainNode.Key ==vkey)
{
return pCi.CurrentChainNode.Data;
}
}
return null;
}

public int Chainnodecount ()
{
int pcount=0;
Cchain.cchainiterator pci=new Cchainiterator (this. Firstchainnode,null);
while (Pci.nextchainnode () ==true)
{
pcount++;
}
return pcount;
}
}
}