java中的浮点和“ do”语句

Question

我正在尝试编写一个充当信用卡交易记录器的程序。我正在记录商店名称和日期以及交易金额。

到目前为止是我的代码：

package pkgeCard;

import java.io.*;

public class eCard {

    public static void main(String[] args) throws NumberFormatException, IOException {
        String company = "eMoney", cardName = "eCard",
                firstName = "John", lastName = "Doe",
                exDate = "05/22", storeName = "", date = "";
        int cardNum = 26648946;
        float maxAmount = 10000.00f, balance = 0.00f, purchAmount = 0.00f;
        char anotherPurchase = 'N';
        BufferedReader br = new BufferedReader(new InputStreamReader(System.in));

        System.out.println("Welcome to eCard");
        {
            do {
                System.out.println("Please enter your transaction store name:");
                storeName = br.readLine();

                System.out.println("Please enter the transaction date:");
                date = br.readLine();

                System.out.println("Please enter your purchase total amount:");
                purchAmount = br.read();
                balance += purchAmount;

                if (purchAmount > maxAmount || balance > maxAmount)
                    System.out.println("Unfortunately, you have exceeded your card's maximum balance. Your transaction has been declined");

                else {
                    System.out.printf("You made a purchase at " + storeName + " on " + date + " for the amount of $ %,.2f ", purchAmount);
                    System.out.printf("You have a remaining balance of $ %,.2f ", (maxAmount - balance));
                }
                System.out.print("Would you like to enter another transaction? Y/N ");
                anotherPurchase = br.readLine().charAt(0);

            } while (anotherPurchase == 'Y');

            System.out.println("Thank you for using eCard.");
            System.out.printf("Your remaining balance is $ %,.2f ", (maxAmount - balance));
        }
    }
}

我在使用do语句和美元金额格式时遇到麻烦。当我运行程序并输入大于最大金额的金额时，它会说：

请输入您的购买总额：50000.00您于05/14在梅西百货购买了一笔金额为$ 53.00的商品。您还有$ 9,947.00的余额。您想输入另一笔交易吗？是/否感谢您使用eCard。您的余额为$ 9,947.00

不仅do语句搞砸了，它不是在捕捉购买金额的值，而是说$ 53。我对Java完全陌生，因此任何见识都将不胜感激。

Answer 1

尝试更改为BigDecimal而不是float，因为在处理货币时会更准确。