Question

我正在尝试创建货币转换器。我在我的代码中弹出一个货币表作为链接。我想询问用户是否要兑换成美元。我认为括号的放置有误。我很乐意，如果有人能看到这个节目，让我知道他们的想法:)谢谢你的帮助

package Testing;

import java.awt.Color;
import java.awt.Desktop;
import java.awt.Font;
import java.util.Scanner;

import javax.swing.JEditorPane;
import javax.swing.JFrame;
import javax.swing.SwingUtilities;
import javax.swing.event.HyperlinkEvent;
import javax.swing.event.HyperlinkListener;

public class Test1 {
    public static JFrame f = new JFrame("HyperlinkListener");

    public static void main(final String[] args) {

        Scanner stdin = new Scanner(System.in); // creates new scanner

        System.out.println("Hello, welcome to currency convertor"); //intro
        System.out.println();
        System.out.println("You will be able to convert from, and to, the U.S dollar"); //asks user what to think of what they want to convert
        System.out.println("A box is going to appear, please click it and find your specific exchange rate. "); // has user go to exchange rate table

        SwingUtilities.invokeLater(new Runnable() { //opens a text box that allows the user to click on a link that brings them to the website
            @Override
            public void run() { //runs the window to open link
                Font font = new Font("Serif", Font.BOLD, 12); //picks font size and font type
                JEditorPane jep = new JEditorPane();
                jep.setContentType("text/html"); //set content as html
                jep.setFont(font);
                jep.setText(
                        "Click <a href='http://www.x-rates.com/table/?from=USD&amount=1'> this button </a> to see the table."); //the text that will be displayed
                jep.setEditable(false); //to ensure the user can't type in the box
                jep.setOpaque(true); // to ensure the box isn't see through
                jep.setBackground(Color.RED); // change box color to red
                jep.setSize(100, 500); //set size of link box
                jep.addHyperlinkListener(new HyperlinkListener() {
                    @Override
                    public void hyperlinkUpdate(final HyperlinkEvent hle) {
                        if (HyperlinkEvent.EventType.ACTIVATED.equals(hle.getEventType())) {
                            System.out.println(hle.getURL());
                            Desktop desktop = Desktop.getDesktop();
                            try {
                                desktop.browse(hle.getURL().toURI());
                            } catch (Exception ex) {
                                ex.printStackTrace();
                            }
                        }
                    }
                });

                f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                f.add(jep);
                f.pack();
                f.setLocation(400, 200); //says where on the screen the box will be
                f.setVisible(true);
            }
        });

        boolean yes = true;

        double exchangerate, currency, currencyfrom, end;

        System.out.println("If you are converting to the U.S dollar, say true. If not, say false");
        {
            if (true) {
                boolean correct = true;
                do { //while loop, so the user can repeat
                    System.out.println("What is the currency you're converting from");
                    currency = stdin.nextDouble();
                    System.out.println("How many?");
                    currencyfrom = stdin.nextDouble();
                    System.out.println("What is the exchange rate?");
                    exchangerate = stdin.nextDouble();
                    end = currencyfrom / exchangerate;
                    System.out.printf("You have %d %d", end, currency);
                    System.out.println("Do you want to do another, say true if you do, say false if not");
                    yes = stdin.nextBoolean(); //if they say true, it will go through again
                } while (yes);
                System.out.println("Thank you for using the currency converter!"); //prints out when the user is done 

            }
            {
                if (false) {
                    do { //while loop, so the user can repeat

                        System.out.println("What is the currency you're converting to");
                        currency = stdin.nextDouble();
                        System.out.println("How many?");
                        currencyfrom = stdin.nextDouble();
                        System.out.println("What is the exchange rate?");
                        exchangerate = stdin.nextDouble();
                        end = currencyfrom * exchangerate;
                        System.out.printf("You have %d %d", end, currency);
                        System.out.println("Do you want to do another, say true if you do, say false if not");
                        yes = stdin.nextBoolean(); //if they say true, it will go through again
                    } while (correct);
                }
                System.out.println("Thank you for using the currency converter!"); //prints out when the user is done                      

            }
        }
    }
}

Answer 1

您的correct变量是在 if（true）块中声明的，其范围仅限于此块， do-while（正确）< / em>阻止。

只需将此声明移到这些块之外，就像使用yes变量一样。

boolean yes = true; boolean correct = true; double exchangerate, currency, currencyfrom, end; ....

简单的Java货币转换器错误

1 个答案: