C#

Public Shared Sub Beep()
      Try 
            New UIPermission(UIPermissionWindow.SafeSubWindows).Demand
      Catch exception1 As  Exception
            Try 
                  New UIPermission(UIPermissionWindow.SafeTopLevelWindows).Demand
            Catch exception2 As  Exception
                  Return
            End Try
      End Try
      UnsafeNativeMethods.MessageBeep(0)
End Sub

<DllImport("user32", CharSet:=CharSet.Unicode)> _
Friend Shared Function MessageBeep(ByVal uType As Integer) As Integer
End Function

'You can make different sounds my passing one of these to uType:
Public Const MB_ICONASTERISK As Integer = 64
Public Const MB_ICONEXCLAMATION As Integer = 48
Public Const MB_ICONHAND As Integer = 16
Public Const MB_ICONQUESTION As Integer = 32
Public Const MB_OK As Integer = 0 'Default

for (Iterator i = myList.iterator(); i.hasNext();)
{
   String tmp = (String) i.next();
}

foreach(String tmp in myList)
{
}

for (int i = 0; i < myList.size(); i++)
{
   String tmp = (String) myList.get(i);
}

for (int i = 0; i < 8; ++i)
{
    // You need to cast.
    Customer cust = (Customer)customers[i];
}

foreach (Customer cust in customers)
{
    // cust is now of correct type Customer.
} 

// Calling code somehow knows that customers[4] needs some special handling.
for (int i = 0; i < 8; ++i)
{
   if (i == 4)
   {
      Customer cust = (Customer)customers[i];
      DoSumthingWithCustomer(cust);
   }
}

// Calling code only knows it needs to call a method for each customer object.
foreach (Customer cust in customers)
{
    // cust is now of correct type Customer.
    cust.DoSumthing();
}

protected void DoSomething(MySortedStringList sortedElements, string[] buffer)
{
   int i = 0;
   foreach (string element in sortedElements)
   {
      buffer[i++] = element;
   }

}

public class MyForm: Form
{
   private Button button;

   public MyForm()
   {
      button = new Button();
      this.Controls.Add(button);

      AcceptButton = button;
   }
}