Changes

BankAccount *account1;

account1 = [[BankAccount alloc] init];

id object1;

object1 = [[SavingsAccount alloc] init];

[object1 setAccount: 4543455 andBalance: 3010.10];

[object1 release];  object1 = [[CustomerInfo alloc] init];  [object1 displayInfo];

Dynamic typing is about being able to dynamically assign objects of different types to a variable while the code is executing. The concept of ''dynamic binding'' involves the ability to to have the same level of flexibility when calling methods on dynamically typed objects.