The Algorithms logo
The Algorithms
AboutDonate

Integer To Roman

S
B
L
A
M
A
x
package com.thealgorithms.conversions;

/**
 * Converting Integers into Roman Numerals
 *
 * <p>
 * ('I', 1); ('IV',4); ('V', 5); ('IX',9); ('X', 10); ('XL',40); ('L', 50);
 * ('XC',90); ('C', 100); ('D', 500); ('M', 1000);
 */
public class IntegerToRoman {

    private static int[] allArabianRomanNumbers
            = new int[]{1000, 900, 500, 400, 100, 90, 50, 40, 10, 9, 5, 4, 1};
    private static String[] allRomanNumbers
            = new String[]{"M", "CM", "D", "CD", "C", "XC", "L", "XL", "X", "IX", "V", "IV", "I"};

    // Value must be > 0
    public static String integerToRoman(int num) {
        if (num <= 0) {
            return "";
        }

        StringBuilder builder = new StringBuilder();

        for (int a = 0; a < allArabianRomanNumbers.length; a++) {
            int times = num / allArabianRomanNumbers[a];
            for (int b = 0; b < times; b++) {
                builder.append(allRomanNumbers[a]);
            }

            num -= times * allArabianRomanNumbers[a];
        }

        return builder.toString();
    }

    public static void main(String[] args) {
        System.out.println(IntegerToRoman.integerToRoman(2131));
    }
}