C#

List<bool> listDoorStatus= new List<bool>();
for (int i = 1; i <= 100; i++)
            {
                for (int j = i; j <= numberOfDoors; j += i)
                {
                    listDoorStatus[j - 1] = !listDoorStatus[j - 1];
                }
            }
            StringBuilder sb = new StringBuilder();
            foreach (var item in listDoorStatus)
            {
                if (item)
                {
                    sb.Append("@");
                }
                else
                {
                    sb.Append("#");
                }
            } return sb.toString()

SqlConnection con = new SqlConnection(@"Data Source=\=DAVIES-SERVER\SQLEXPRESS;database=Artemis Data;Integrated Security=True");

// code example

    public interface IBeing
    {
        string BName { get; set; }
        Type BType { get; set; }
    }

    public interface IBeing<T> : IBeing where T : class
    {
        T Value { get; set; }
    }
    
    
    public class Being<T> : IBeing where T : class
    {
        public Being(string name, T value)
        {
            Value = value;
            BName = name;
        }

        public T Value { get; set; }
        public string BName { get; set; }
        public Type BType { get; set; }
    }
    
 // example classes that implement the interface:
 
     public class Human : IBeing
    {
        public Human(string name)
        {
            BName = name;
        }

        public Type BType { get; set; }

        public string BName { get; set; }
    }

    public class Dog : IBeing
    {
        public Dog(string name)
        {
            BName = name;
        }

        public Type BType { get; set; }

        public string BName { get; set; }
    }
    
   // a collection
    
    public class BeingCache
    {
        public BeingCache()
        {
            Beings = new List<IBeing>();
        }

        public List<IBeing> Beings { get; }

        public IBeing AddBeing<T>(string name, T value) where T : class
        {
            Being<T>  newbeing = new Being<T>(name, value);
            newbeing.BType = typeof(T);
            Beings.Add(newbeing);
            return newbeing;
        }
    }

// usage example

            BeingCache beingCache = new BeingCache();

            Human h1 = new Human("h1");

            Dog d1 = new Dog("d1");
   
            IBeing being1 = beingCache.AddBeing<Human>("Jack", h1);
            IBeing being2 = beingCache.AddBeing<Dog>("Rover", d1);

            IBeing being1human = beingCache.Beings[0];
            IBeing being2dog = beingCache.Beings[1];

SQLiteParameter[] param = {};
// MessageBox.Show("ran?");
 customerList.Rows.Clear();

 DataTable searchinfo = database.query_search("SELECT id, firstname, lastname FROM customers", param);

 foreach (DataRow row in searchinfo.Rows)
 {
     customerList.Rows.Add(row[0].ToString(), row[1].ToString() + " " + row[2].ToString());
 }
 statusLabel.Text = searchinfo.Rows.Count.ToString() + " row(s) returned";

private void customerList_CellDoubleClick(object sender, DataGridViewCellEventArgs e)
{
    int index = e.RowIndex;

    DataGridViewRow row = customerList.Rows[index];
    String cid = row.Cells[0].Value.ToString();

    editcustomer editdiag = new editcustomer();
    editdiag.id = cid;
    editdiag.ShowDialog();
}

private void search_TextChanged(object sender, EventArgs e)
{
    if(queryInterval.Enabled == false)
        queryInterval.Start();
}

public void queryInterval_Tick(object sender, EventArgs e)
{
    if (lastQuery == search.Text)
    {
        queryInterval.Stop();
    }
    else
    {
        if (search.Text.Trim() != "" && search.Text.Length >= 3)
        {
            customerList.Rows.Clear();

            SQLiteParameter[] param = {
            new SQLiteParameter("@search", "%" + search.Text + "%") //used direct string for debug //search.Text)
        };

            DataTable searchinfo = database.query_search("SELECT id, firstname, lastname FROM customers WHERE firstname LIKE @search OR lastname LIKE @search", param);

            foreach (DataRow row in searchinfo.Rows)
            {
                customerList.Rows.Add(row[0].ToString(), row[1].ToString() + " " + row[2].ToString());
            }

            statusLabel.Text = searchinfo.Rows.Count.ToString() + " row(s) returned";
        }
        else if (search.Text.Trim() == "")
        {
            SQLiteParameter[] param = { };

            customerList.Rows.Clear();

            DataTable searchinfo = database.query_search("SELECT id, firstname, lastname FROM customers", param);

            foreach (DataRow row in searchinfo.Rows)
            {
                customerList.Rows.Add(row[0].ToString(), row[1].ToString() + " " + row[2].ToString());
            }
            statusLabel.Text = searchinfo.Rows.Count.ToString() + " row(s) returned";
        }
        else if (search.Text.Length < 3 && search.Text.Trim() != "")
        {
            //we do nothing
        }

        lastQuery = search.Text;
    }
}

private void editcustomer_FormClosed(object sender, FormClosedEventArgs e)
 {
     customers custForm = new customers();
     custForm.refresh(sender, e);
     custForm.customers_Load(sender, e);
 }

private void editcustomer_FormClosed(object sender, FormClosedEventArgs e)
{
    customers custForm = new customers();
    custForm.lastQuery = "";
    custForm.queryInterval.Start();
}