private static void BabyAccountExample()
{
IAccount b = new BabyAccount();
b.PayInFunds(50);
Console.WriteLine("Balance: {0}", b.GetBalance());
Console.WriteLine("Trying to withdraw 20");
if (b.WithdrawFunds(20))
{
Console.WriteLine("Balance: {0}", b.GetBalance());
}
else
{
Console.WriteLine("Not allowed");
}
/* You can write the code below: */
IAccount b2 = new BabyAccount2();
b2.PayInFunds(50);
Console.WriteLine("Balance: {0}", b.GetBalance());
/* This works because, although BabyAccount2 does not have a PayInFunds method, the base class does.
* This means that the PayInFunds method from the BankAccount class is used at this point.
* Instances of the BabyAccount2 class have abilities which they pick up from their base class. In
* fact, at the moment, the BabyAccount2 class has no behaviors of its own; it gets everything from
* its base class. */
}
public void InheritanceFromBaseClass()
{
IAccount account = new BabyAccount();
account.PayInFunds(50);
// This works because, although BabyAccount does not have a PayInFunds method, the base class does.
// This means that the PayInFunds method from the BankAccount class is used at this point.
// Instances of the BabyAccount class have abilities which they pick up from their base class.
// In fact, at the moment, the BabyAccount class has no behaviors of its own; it gets everything from its base class.
// A program can use the is and as operators when working with class hierarchies and interfaces.
// The is operator determines if the type of a given object is in a particular class hierarchy or implements
// a specified interface. You apply the is operator between a reference variable and a type or
// interface and the operator returns true if the reference can be made to refer to objects of that type.
if (account is IAccount)
{
Console.WriteLine("acc is IAccount");
}
}