Java练习 罗马数字转换

import java.util.Scanner;

//罗马数字转换
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        System.out.println("输入数字字符串");
        String number = sc.next();

        StringBuffer result = new StringBuffer();
        if(checkNum(number)) {
            for (int i = 0; i < number.length(); i++) {
                String c = getLuoMa(number.charAt(i));
                result.append(c);
            }
        }else{
            System.out.println("请输入正确的数字");
        }

        System.out.println(result);
    }
    public static boolean checkNum(String number) {
        if (number.length() == 0 || number.length() > 9){
            return false;
        }

        for (int i = 0; i < number.length(); i++) {
            char n = number.charAt(i);
            if (n < '0' || n > '9') {
                return false;
            }
        }

        return true;
    }

    public static String getLuoMa(int number) {
        String[] numLuoMa = {" ","Ⅰ","Ⅱ","Ⅲ","Ⅳ","Ⅴ","Ⅵ","Ⅶ","Ⅷ","Ⅸ"};
        return numLuoMa[number - 48]; //48对应数字0，如果输入1，对应ASCII码的49，那么减去48还是1
    }
}