static void Main()
{
IBankAccount venusAccount = new SaverAccount();
IBankAccount jupiterAccount = new GoldAccount();
venusAccount.PayIn(200);
venusAccount.Withdraw(100);
WriteLine(venusAccount.ToString());
jupiterAccount.PayIn(500);
jupiterAccount.Withdraw(600);
jupiterAccount.Withdraw(100);
WriteLine(jupiterAccount.ToString());
}
static void Main()
{
IBankAccount venusAccount = new SaverAccount(); //using default constructor, balance is 0
IBankAccount jupiterAccount = new GoldAccount();
/*����instance from a interface instead of class���ĺô�����Inversion Of Control(���Ʒ�ת):
* object is typically not known at compile time. you can call only methods that are part of
* this interface through these references �� if you want to call any methods implemented by
* a class that are not part of the interface, you need to cast the reference to the appropriate type.
* But in the example code, you were able to call ToString() (not implemented by IBankAccount) without
* any explicit cast, purely because ToString() is a System.Object method, so the C# compiler knows
* that it will be supported by any class.*/
venusAccount.PayIn(200);
venusAccount.Withdraw(100);
Console.WriteLine(venusAccount.ToString()); //override ToString
jupiterAccount.PayIn(500);
jupiterAccount.Withdraw(600); //withdraw attempt failed
jupiterAccount.Withdraw(100);
Console.WriteLine(jupiterAccount.ToString());
//Interface references can in all respects be treated as class references �� but the power of an interface reference is that it can refer to any class that implements that interface.
}