// "Subject"
abstract class Stock
{
protected string symbol;
protected double price;
private ArrayList investors = new ArrayList();
// Constructor
public Stock(string symbol, double price)
{
this.symbol = symbol;
this.price = price;
}
public void Attach(Investor investor)
{
investors.Add(investor);
}
public void Detach(Investor investor)
{
investors.Remove(investor);
}
public void Notify()
{
foreach (Investor investor in investors)
{
investor.Update(this);
}
Console.WriteLine("");
}
// Properties
public double Price
{
get { return price; }
set
{
price = value;
Notify();
}
}
public string Symbol
{
get { return symbol; }
set { symbol = value; }
}
}
// "ConcreteSubject"
class IBM : Stock
{
// Constructor
public IBM(string symbol, double price)
: base(symbol, price)
{
}
}
