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所以我有一个家庭作业，我必须能够取Roman numeral，反之亦然。我知道如何从数字到字母，但是给数字的字母让我感到困惑。我需要帮助，因为我编写了我的程序和罗马数字来编号。例如，如果我尝试做，XCIX == 99，我得到199。但如果我做的罗马数字2014，那是有效的。另外如果我只输入一个字母，我会得到0。我只需要帮助了解我需要做什么来解决问题。将罗马数字转换为数字逻辑错误java
import java.util.HashMap;
import java.util.Scanner;
public class Apweek2 {
public static void main(String[] args) {
Scanner userinput = new Scanner(System.in);
System.out.print("enter a number to convert to roman numerals: ");
int input = userinput.nextInt();
String[] rv = { "I", "IV", "V", "IX", "X", "XL", "L", "XC", "C", "CD",
"D", "CM", "M" };
int[] values_for_rv = { 1, 4, 5, 9, 10, 40, 50, 90, 100, 400, 500, 900,
1000 };
System.out.print("enter a roman numeral: ");
String roman_numeral = userinput.next();
int sum = 0;
String two_spot = null;
String last_value = null;
for (int i = 1, j = 0; j < roman_numeral.length()
&& i < roman_numeral.length(); i++, j++) {
last_value = roman_numeral.substring(j, i);
char roman_noodles = roman_numeral.charAt(i);
char raman_noodles = roman_numeral.charAt(j);
String roman_values = Character.toString(roman_noodles);
two_spot = last_value + roman_values;
if (two_spot.contains(rv[1])) {
sum = sum + values_for_rv[1];
}
if (two_spot.contains(rv[3])) {
sum = sum + values_for_rv[3];
}
if (two_spot.contains(rv[5])) {
sum = sum + values_for_rv[5];
}
if (two_spot.contains(rv[7])) {
sum = sum + values_for_rv[7];
}
if (two_spot.contains(rv[9])) {
sum = sum + values_for_rv[9];
}
if (two_spot.contains(rv[11])) {
sum = sum + values_for_rv[11];
}
if (!(two_spot.equals(rv[1])) && !(two_spot.equals(rv[3]))
&& !(two_spot.equals(rv[5])) && !(two_spot.equals(rv[7]))
&& !(two_spot.equals(rv[9])) && !(two_spot.equals(rv[11]))) {
if (raman_noodles == 'I') {
sum = sum + 1;
}
if (raman_noodles == 'V') {
sum = sum + 5;
}
if (raman_noodles == 'X') {
sum = sum + 10;
}
if (raman_noodles == 'L') {
sum = sum + 50;
}
if (raman_noodles == 'C') {
sum = sum + 100;
}
if (raman_noodles == 'D') {
sum = sum + 500;
}
if (raman_noodles == 'M') {
sum = sum + 1000;
}
}
}
System.out.println("converted roman numeral is: " + sum);
String inputconversion = inputtoroman(input);
System.out.print("Converted number is: " + inputconversion);
}
public static String inputtoroman(int x) {
String s1 = "";
String s2 = "";
String s3 = "";
String s4 = "";
String s5 = "";
String s6 = "";
String s7 = "";
String s8 = "";
String s9 = "";
String s10 = "";
String s11 = "";
String s12 = "";
String s13 = "";
while (x >= 1000) {
s1 += "M";
x -= 1000;
}
while (x >= 900) {
s2 += "CM";
x -= 900;
}
while (x >= 500) {
s3 += "D";
x -= 500;
}
while (x >= 400) {
s4 += "CD";
x -= 400;
}
while (x >= 100) {
s5 += "C";
x -= 100;
}
while (x >= 90) {
s6 += "XC";
x -= 90;
}
while (x >= 50) {
s7 += "L";
x -= 50;
}
while (x >= 40) {
s8 += "XL";
x -= 40;
}
while (x >= 10) {
s9 += "X";
x -= 10;
}
while (x >= 9) {
s10 += "IX";
x -= 9;
}
while (x >= 5) {
s11 += "V";
x -= 5;
}
while (x >= 4) {
s12 += "IV";
x -= 4;
}
while (x >= 1) {
s13 += "I";
x -= 1;
}
String combined = s1 + s2 + s3 + s4 + s5 + s6 + s7 + s8 + s9 + s10
+ s11 + s12 + s13;
return combined;
}
}