How to convert a number to its Roman numeral representation in Kotlin

How to convert a number to its Roman numeral representation in Kotlin.

Here's a step-by-step tutorial on how to convert a number to its Roman numeral representation in Kotlin:

Step 1: Define a function to convert the number

To start, let's define a function called toRoman that takes an integer parameter representing the number we want to convert. This function will return a string representing the Roman numeral equivalent.

fun toRoman(number: Int): String {
    // Implementation will go here
}

Step 2: Create a mapping of Roman numerals

Next, we need to create a mapping of Roman numerals to their corresponding values. In the Roman numeral system, certain letters represent specific values. Here's a table showing the common Roman numerals and their respective values:

Roman Numeral	Value
I	1
IV	4
V	5
IX	9
X	10
XL	40
L	50
XC	90
C	100
CD	400
D	500
CM	900
M	1000

Let's create a map in Kotlin that represents this mapping:

val romanNumerals = mapOf(
    1000 to "M",
    900 to "CM",
    500 to "D",
    400 to "CD",
    100 to "C",
    90 to "XC",
    50 to "L",
    40 to "XL",
    10 to "X",
    9 to "IX",
    5 to "V",
    4 to "IV",
    1 to "I"
)

Step 3: Convert the number to Roman numeral

Now that we have the mapping, we can start converting the number to its Roman numeral representation. We'll use a loop to iterate through the mapping and subtract the corresponding values from the number until it reaches zero.

fun toRoman(number: Int): String {
    var remainingNumber = number
    var romanNumeral = ""

    for ((value, symbol) in romanNumerals) {
        while (remainingNumber >= value) {
            romanNumeral += symbol
            remainingNumber -= value
        }
    }

    return romanNumeral
}

Step 4: Testing the function

Let's test our toRoman function with a few examples:

fun main() {
    println(toRoman(9)) // Output: IX
    println(toRoman(42)) // Output: XLII
    println(toRoman(1994)) // Output: MCMXCIV
}

In the first example, 9 is represented as "IX" in Roman numerals. In the second example, 42 is represented as "XLII". And in the third example, 1994 is represented as "MCMXCIV".

That's it! You now have a function that can convert a number to its Roman numeral representation in Kotlin.