如何在java中添加罗马数字

Question

我在完成计算机科学课程的编程作业时遇到了问题。该程序是添加到罗马数字。我不知道如何开始使用实际将罗马数字相加并输出两个数字之和的代码：这是我迄今为止的主程序代码：

import java.awt.*;
import javax.swing.*;
import java.awt.event.*;

/**
 * Class RomanNumeralCalculator - write a description of the class here
 * 
 * @author (your name) 
 * @version (a version number)
*/
public class RomanNumeralCalculator extends JFrame
{
   public static JPanel panel1, panel2, panel3, panel4;
   public static JLabel main1, main2, label1, label2,label3,label4,image;
   public static JTextField number1, number2;
   public static JTextArea output;
   public static JButton calculate,exit;
   public static String input="Enter"; 
   public static int position;
String num="";
public RomanNumeralCalculator()
{
    super ("Roman Numeral Calculator");
    setSize(1045,740);
    setLocation(0,0);
    Container container = getContentPane();
    container.setBackground(Color.GREEN);

    JLabel image=new JLabel(new ImageIcon("romanNumerals.jpg"));

    panel1=new JPanel();
    panel2=new JPanel();
    panel3=new JPanel();
    panel4=new JPanel();

    panel1.setLayout(new GridLayout(2,7));
    panel1.setBackground(Color.GREEN);
    panel2.setLayout(new FlowLayout());
    panel2.setBackground(Color.MAGENTA);
    panel3.setLayout(new FlowLayout());
    panel3.setBackground(Color.YELLOW);
    panel4.setLayout(new FlowLayout());
    panel4.setBackground(Color.GRAY);

    JLabel main1=new JLabel("Welcome To The Roman Numerals Calculator");
    JLabel main2=new JLabel("BY: Harpreet Singh, Date: 31/10/2013");

    label3=new JLabel("Here are the following numbers that can be used in the calculator:");
    label4=new JLabel("I=1 , V=5 , X=10 , L=50 , C=100 , D=500 , M=1000");

    calculate=new JButton("Calculate");
    exit=new JButton("Exit");

    ButtonHandler handler = new ButtonHandler();
    calculate.addActionListener(handler);
    exit.addActionListener(handler);

    label1=new JLabel("Enter first number in roman numerals:");
    number1=new JTextField("",10);
    label2=new JLabel("Enter second number in roman numerals:");
    number2=new JTextField("",10);

    output=new JTextArea(10,100);
    output.setEditable(false);

    container.setLayout(new BorderLayout());
    container.add(panel1, BorderLayout.NORTH);
    container.add(panel2, BorderLayout.CENTER);
    container.add(panel3, BorderLayout.SOUTH);

    panel1.add(main1);
    panel1.add(main2);
    panel1.add(image);
    panel2.add(label3);
    panel2.add(label4);
    panel3.add(label1);
    panel3.add(number1);
    panel3.add(label2);
    panel3.add(number2);
    panel3.add(calculate);        
    panel3.add(exit);

    setVisible(true);
}

public class ButtonHandler implements ActionListener
{
    public void actionPerformed(ActionEvent e)
    {
        if (e.getSource()==calculate)
        {
            String num1=number1.getText();
            String num2=number2.getText();
            CalculateNumbers x=new CalculateNumbers();
            x.calculations(num1,num2);
        }
        else if (e.getSource()==exit)
        {
            System.exit(0);
        }
    }
}

public static void main (String args[])
{
    /*String choice=JOptionPane.showInputDialog(null, "Please Type In 'Enter' to Continue: ", "Enter", JOptionPane.PLAIN_MESSAGE);
    if ((choice == null) || ((choice != null) && !(choice.equalsIgnoreCase(input))))
    {
    JOptionPane.showMessageDialog(null, "Invalid Password. Please Try Again.");
    System.exit(0);
    }*/
    //else
    //{
    //JOptionPane.showMessageDialog(null, "Correct Password");
    RomanNumeralCalculator application = new RomanNumeralCalculator();
    //}
}

}

Answer 1

先写两个方法

1. 将罗马数字转换为普通数字
2. 将常规数字转换为罗马数字

当用户提供罗马数字输入时，将其转换为常规数字，执行算术运算，最后将结果转换为罗马数字

同时检查Converting Roman Numerals To Decimal和Convert Int to Roman Numeral

Answer 2

创建一个罗马数字类，它将在给定十进制数字的情况下转换您的数字，反之亦然。如果需要，您甚至可以将其设为静态。

这将使您的代码看起来更好，更面向对象。

这里有一个算法解释。

roman number algorithm

Answer 3

       import java.util.Scanner;

        public class Roman {

        public static void main(String[] args) {

        Scanner stdIn = new Scanner(System.in);

         System.out.print("Enter a Roman Number:> ");

          char[] roman = stdIn.nextLine().toCharArray();

    int total = 0;
    for(int i = roman.length-1; i > -1; i--){
        switch(roman[i]){
            case 'I':
                total += value(roman[i]); break;
            case 'V':
            case 'X':
            case 'L':
            case 'C':
            case 'D':
            case 'M':
                if(i != 0 && (value(roman[i-1]) < value(roman[i]))){
                    total += value(roman[i]) - value(roman[i-1]);
                    i--;
                }else{
                    total += value(roman[i]);
                }
                break;
        }
    }
    System.out.println(total);
}

public static int value(char c){
    switch(c){
        case 'I':
            return 1;
        case 'V':
            return 5;
        case 'X':
            return 10;
        case 'L':
            return 50;
        case 'C':
            return 100;
        case 'D':
            return 500;
        case 'M':
            return 1000;
        default:
            return 0;
    }
} }