Question

相对较新的java编程，我的代码输出错误，因为它与swing方面有关

import java.io.*;
import Java.text.DecimalFormat;


public class CurrencyConverter
{
public static void main(string[]args)throws IOException
{
String USDollar;
double USD, Euro, Pounds, Rouble;

BufferedReader dataIn=new BufferedReader (newInputStreamReader(System.in));

System.out.println();
System.out.println("\t\t CURRENCY CONVERTER");
System.out.println("\t\t Please enter the Dollar amount in US DOLLAR");
USDollar=dataIn.readLine();
USD=Double.parseDouble(USDollar);

Rouble=(USD*34.89);
Pounds=(USD*0.61);
      Euro=(USD*0.73);

System.out.println();
System.out.println("\t\tYour given amount $"+USD);
System.out.println("\t\tPounds $"+ Pounds);
System.out.println("\t\tRussian Rouble $"+ Rouble);
System.out.println("\t\tEuro $"+Euro);

}
}

import javax.swing.JOptionPane;

public class CSwing
{
public static void main(String[]args)
{
String USDollar;
double USD,Pounds,Rouble,Euros;

System.out.println("t\tCURRENCY CONVERTER");

USD = JOptionPane.showInputDialog(null,"Please enter the Dollar amount in USD");
dUSD=Double.parseDouble(USD);

Rouble=(USD*34.89);
Pounds=(USD*0.61);
Euro=(USD*0.73);

JOptionPane.showMessageDialog(null, "Your Given Amount: $" +(dUSD)
+"\n\nYour Rouble Conversion is:$"+(Rouble)
+"\n\nYour Pound Conversion is:$"+(Pound)
+"\n\nYour Euro Conversion is:$"+(Euro));
System.exit(0);
}
}

工具输出错误：class, interface, enum expected: import javax.swing.JOptionpane：我用谷歌搜索了这个，试图自己解决它，但我被卡住了。我已经解决了目前存在的所有其他错误，这是唯一剩下的错误，但为什么我遇到这个错误。您对此的帮助将非常感激。

Answer 1

在这一行中：dUSD=Double.parseDouble(USD);您试图从Double解析USD已经是双倍的Double.parseDouble(String S)。

String需要将Double参数传递给它。不是import javax.swing.JOptionPane; public class CSwing { public static void main(String[] args) { String usd; double dUSD, pounds, rouble, euros; System.out.println("t\tCURRENCY CONVERTER"); usd = JOptionPane.showInputDialog(null, "Please enter the Dollar amount in USD"); dUSD = Double.parseDouble(usd); rouble = (dUSD * 34.89); pounds = (dUSD * 0.61); euros = (dUSD * 0.73); JOptionPane.showMessageDialog(null, "Your Given Amount: $" + (dUSD) + "\n\nYour Rouble Conversion is:$ " + (rouble) + "\n\nYour Pound Conversion is:$ " + (pounds) + "\n\nYour Euro Conversion is:$ " + (euros)); System.exit(0); } }。

快速修复：

CurrencyConverter

至于你的import java.io.*; public class CurrencyConverter { public static void main(String[] args) throws IOException { String usDollar; double usd, euro, pounds, rouble; BufferedReader dataIn = new BufferedReader(new InputStreamReader(System.in)); System.out.println(); System.out.println("\t\t CURRENCY CONVERTER"); System.out.println("\t\t Please enter the Dollar amount in US DOLLAR"); usDollar = dataIn.readLine(); usd = Double.parseDouble(usDollar); rouble = (usd * 34.89); pounds = (usd * 0.61); euro = (usd * 0.73); System.out.println(); System.out.println("\t\tYour given amount $" + usd); System.out.println("\t\tPounds $" + pounds); System.out.println("\t\tRussian Rouble $" + rouble); System.out.println("\t\tEuro $" + euro); } }，一切似乎都只是一些小的印刷错误。

修正：

{{1}}

Answer 2

您必须在所有类声明之前导入所有内容。因此，使用所有其他声明将import javax.swing.JOptionPane;移至顶部。或者像@assylias指出的那样只是将两个类分成不同的文件。哦，并且包import Java.text.DecimalFormat;不存在，请将'j'改为'Java'小写。

运行导入javax.swing.JOptionpane时出错

2 个答案: