public class CheckingAccount extends BankAccount { private int transactionCount; public CheckingAccount() { super(); // unn�tig transactionCount = 0; } public CheckingAccount(double initialBalance) { super(initialBalance); transactionCount = 0; } public void deposit(double amount) { super.deposit(amount); transactionCount++; } public void withdraw(double amount) { super.withdraw(amount); transactionCount++; } public String toString() { return "CheckingAccount[b = " + getBalance() + ", t = " + transactionCount + "]"; } }