Conversion Integer to Roman Numeral

Question

i want to convert integer to roman numeral. As we know, format for roman numeral is like this:

• 1 = I
• 5 = V
• 10 = X
• 50 = L
• 100 = C
• 500 = D
• 1000 = M

For example, if we have number 497, it will be CDXCVII.

In Java, i know we can use Switch Case for the condition. Is there any idea to implement this in apex?

Answer 1

I don't think there is any native functionality to implement this. So you need to write custom logic to implement this. As Java and Apex share similar code concept so you can take help from there

public static String IntegerToRomanNumeral(int input) {
    if (input < 1 || input > 3999)
        return "Invalid Roman Number Value";
    String s = "";
    while (input >= 1000) {
        s += "M";
        input -= 1000;        }
    while (input >= 900) {
        s += "CM";
        input -= 900;
    }
    while (input >= 500) {
        s += "D";
        input -= 500;
    }
    while (input >= 400) {
        s += "CD";
        input -= 400;
    }
    while (input >= 100) {
        s += "C";
        input -= 100;
    }
    while (input >= 90) {
        s += "XC";
        input -= 90;
    }
    while (input >= 50) {
        s += "L";
        input -= 50;
    }
    while (input >= 40) {
        s += "XL";
        input -= 40;
    }
    while (input >= 10) {
        s += "X";
        input -= 10;
    }
    while (input >= 9) {
        s += "IX";
        input -= 9;
    }
    while (input >= 5) {
        s += "V";
        input -= 5;
    }
    while (input >= 4) {
        s += "IV";
        input -= 4;
    }
    while (input >= 1) {
        s += "I";
        input -= 1;
    }    
    return s;
}

Converting Integers to Roman Numerals - Java

Answer 2

Represent the number with just I, and then we replace the characters in ascending value of the roman characters.

String intToRoam(integer Num){
  return  'I'.repeat(Num)
            .replace('IIIII', 'V')
            .replace('IIII', 'IV')
            .replace('VV', 'X')
            .replace('VIV', 'IX')
            .replace('XXXXX', 'L')
            .replace('XXXX', 'XL')
            .replace('LL', 'C')
            .replace('LXL', 'XC')
            .replace('CCCCC', 'D')
            .replace('CCCC', 'CD')
            .replace('DD', 'M')
            .replace('DCD', 'CM');
}

system.debug('Romanstr ' + intToRoam(497));