import java.util.Scanner;

/**
 * <p>
 * Sample "savings account" program for CIT591.
 * </p>
 * <p>
 * The user starts with a balance of zero, and can perform the following
 * operations:
 * <ul>
 * <li>D -- Deposit money into the account</li>
 * <li>W -- Withdraw money from the account</li>
 * <li>C -- Check how much money is in the account</li>
 * <li>Q -- Quit the program</li>
 * </ul>
 * The above letters may also be entered in lowercase.
 * </p>
 * 
 * @author Dave Matuszek
 * @version Sep 15, 2008
 */
public class SavingsAccount {

	Scanner scanner;

	public static void main(String[] args) {
		new SavingsAccount().run();
	}

	void run() {
		double balance = 0;
		scanner = new Scanner(System.in);

		System.out.print("What do you want to do (CDWQ)? ");
		String request = scanner.next();
		request = request.toLowerCase();

		while (request.charAt(0) != 'q') {
            double amount;
			switch (request.charAt(0)) {
				case 'c':
					System.out.println("Your balance is " + balance);
					break;
				case 'd':
					System.out.print("Enter an amount: ");
					amount = scanner.nextDouble();
					balance = balance + amount;
					break;
				case 'w':
					balance = doWithdrawal(balance);
					break;
			}
			System.out.print("What do you want to do (CDWQ)? ");
			request = scanner.next();
			request = request.toLowerCase();
		}
	}

	private double doWithdrawal(double balance) {
		double amount;
		System.out.print("Enter an amount: ");
		amount = scanner.nextDouble();
		if (amount > balance) {
			System.out.println("Sorry, Dave, I can't do that.");
		} else {
			assert amount <= balance;
			balance = balance - amount;
		}
		return balance;
	}

}