ssukhpinder

ClaimApprover junior = new Manager();
ClaimApprover sukhpinder = new Manager();
ClaimApprover singh = new SeniorManager();
junior.SetHierarchy(sukhpinder);
sukhpinder.SetHierarchy(singh);

Claim c1 = new Claim() { amount = 999, Id = 1001 };
Claim c2 = new Claim() { amount = 10001, Id = 1002 };

junior.ApproveRequest(c1);

ssukhpinder

public class SeniorManager : ClaimApprover
{
    public override void ApproveRequest(Claim claim)
    {
        if (claim.amount > 1000 && claim.amount <= 10000)
        {
            System.Console.WriteLine($"Claim reference {claim.Id} with amount {claim.amount} is approved by Senior Manager");
        }
        else
        {

ssukhpinder

public class Manager : ClaimApprover
{
    public override void ApproveRequest(Claim claim)
    {
        if (claim.amount >= 100 && claim.amount <= 1000)
        {
            System.Console.WriteLine($"Claim reference {claim.Id} with amount {claim.amount} is approved by Manager");
        }
        else if (claimApprover != null)
        {

ssukhpinder

public class Junior : ClaimApprover
{
    public override void ApproveRequest(Claim claim)
    {
        System.Console.WriteLine("Cannot approve");
    }
}

ssukhpinder

public abstract class ClaimApprover
{
    protected ClaimApprover claimApprover;
    public void SetHierarchy(ClaimApprover claimApprover)
    {
        this.claimApprover = claimApprover;
    }
    public abstract void ApproveRequest(Claim claim);
}

ssukhpinder

static void Main(string[] args)
{
    Chatroom chatroom = new Chatroom();
    User Jennifer = new UserPersona(Username.Jennifer.ToString());
    User Ashley = new UserPersona(Username.Ashley.ToString());
    User David = new UserPersona(Username.David.ToString());
    User Scott = new UserPersona(Username.Scott.ToString());

    chatroom.Register(Jennifer);
    chatroom.Register(Ashley);

ssukhpinder

class UserPersona : User
{
    public UserPersona(string name) : base(name) { }

    public override void DM(string from, string message) => base.DM(from, message);

}

ssukhpinder

public class User
{
    private Chatroom _chatroom;
    private string _name;
    public User(string name) => this._name = name;

    public string Name => _name;

    public Chatroom Chatroom
    {

ssukhpinder

public class Chatroom : AChatroom
{
    private Dictionary<string, User> _users = new Dictionary<string, User>();
    public override void Post(string fromUser, string toUser, string msg)
    {
        User participant = _users[toUser];

        if (participant != null)
        {
            participant.DM(fromUser, msg);

ssukhpinder

public abstract class AChatroom
{
    public abstract void Register(User user);
    public abstract void Post(string fromUser, string toUser, string msg);
}