shoppingcartapplication.java

JAVA编程 SSD3 UNIT1完全答案 满分作业!! CMU经典课程

import java.io.*;
import java.util.*;

public class ShoppingCartApplication {

	private static BufferedReader stdIn = new BufferedReader(
			new InputStreamReader(System.in));

	private static PrintWriter stdOut = new PrintWriter(System.out, true);

	private static PrintWriter stdErr = new PrintWriter(System.err, true);

	private ShoppingCart cart;

	public static void main(String[] args) throws IOException {

		ShoppingCartApplication application = new ShoppingCartApplication();

		application.run();
	}

	private void run() throws IOException {

		cart = new ShoppingCart();

		int choice = getChoice();

		while (choice != 0) {

			if (choice == 1) {
				cart.addProduct(readProduct());
			} else if (choice == 2) {
				stdOut.println(cart.toString());
			} else if (choice == 3) {
				stdOut.println(cart.getTotalValue());
			}

			choice = getChoice();
		}
	}

	private int getChoice() throws IOException {

		do {

			int input;

			try {
				stdErr.println();
				stdErr.print("[0]  Quit\n" + "[1]  Add Product\n"
						+ "[2]  Display Products\n" + "[3]  Display Total\n"
						+ "choice>");
				stdErr.flush();

				input = Integer.parseInt(stdIn.readLine());

				if (0 <= input && 3 >= input) {

					return input;

				} else {
					stdErr.println("Invalid choice:  " + input);
				}
			} catch (NumberFormatException nfe) {
				stdErr.println(nfe);
			}
		} while (true);
	}

	private Product readProduct() throws IOException {

		final String DELIM = "_";

		String name = "";
		int quantity = 0;
		double price = 0.0;

		/* PLACE YOUR CODE HERE */

		StringTokenizer tknzr;
		int numOfTokenizer;

		do {
			stdErr.println("product [name_qty_price]>");
			tknzr = new StringTokenizer(stdIn.readLine(), DELIM);
			numOfTokenizer = tknzr.countTokens();

			try {
				name = tknzr.nextToken();
				quantity = Integer.parseInt(tknzr.nextToken());
				price = Double.parseDouble(tknzr.nextToken());
			} catch (NumberFormatException nef) {
				stdErr.println(nef.toString());
			} catch (Exception exx) {
			}

			if (0 >= quantity || 0 >= price || tknzr.hasMoreTokens()) 
			{
				stdErr.println("Invalid Enter!");
				name = "";
				quantity = 0;
				price = 0.0;
			}
		} while (0 >= quantity || 0 >= price || 3 != numOfTokenizer);

		return new Product(name, quantity, price);
	}
}