Roman Numeral in C#

Roman Numeral

in C#

Welcome to the Roman Numeral in C# page! Here, you'll find the source code for this program as well as a description of how the program works.

Current Solution

if (args is not [var input])
    return ExitWith("Usage: please provide a string of roman numerals");

if (!TryRomanToInt(input.AsSpan().Trim(), out int value))
    return ExitWith("Error: invalid string of roman numerals");

Console.WriteLine(value);
return 0;

static bool TryRomanToInt(ReadOnlySpan<char> roman, out int result)
{
    result = 0;
    if (roman.Length == 0)
        return true;

    int prev = 0;

    for (int i = roman.Length - 1; i >= 0; i--)
    {
        if (!TryGetValue(roman[i], out int current))
            return false;

        if (current < prev)
            result -= current;
        else
            result += current;

        prev = current;
    }

    return true;
}

static bool TryGetValue(char c, out int value)
{
    value = char.ToUpper(c) switch
    {
        'I' => 1,
        'V' => 5,
        'X' => 10,
        'L' => 50,
        'C' => 100,
        'D' => 500,
        'M' => 1000,
        _ => 0
    };

    return value != 0;
}

static int ExitWith(string message)
{
    Console.WriteLine(message);
    return 1;
}

Roman Numeral in C# was written by:

• Parker Johansen
• Ștefan-Iulian Alecu

If you see anything you'd like to change or update, please consider contributing.

How to Implement the Solution

No 'How to Implement the Solution' section available. Please consider contributing.

How to Run the Solution

No 'How to Run the Solution' section available. Please consider contributing.