public static string ToRomanNumerals(this int?num, NumeralStyles style = NumeralStyles.Subtractive)
{
var sb = new StringBuilder();
if (num.HasValue && num != 0)
{
var thousands = Math.DivRem(num.Value, 1000, out var tRem);
var hundreds = Math.DivRem(tRem, 100, out var hRem);
var tens = Math.DivRem(hRem, 10, out var tenRem);
switch (style)
{
case NumeralStyles.Subtractive:
sb.AppendRepeat(Numerals.M, thousands);
SubtractiveNumerals(sb, hundreds, (Numerals.C, Numerals.D, Numerals.M));
SubtractiveNumerals(sb, tens, (Numerals.X, Numerals.L, Numerals.C));
SubtractiveNumerals(sb, tenRem, (Numerals.I, Numerals.V, Numerals.X));
break;
case NumeralStyles.Additive:
sb.AppendRepeat(Numerals.M, thousands);
AdditiveNumerals(sb, hundreds, (Numerals.C, Numerals.D, Numerals.M));
AdditiveNumerals(sb, tens, (Numerals.X, Numerals.L, Numerals.C));
AdditiveNumerals(sb, tenRem, (Numerals.I, Numerals.V, Numerals.X));
break;
}
}
return(sb.ToString());
}
public static string ToRomanNumerals(this int num, NumeralStyles style = NumeralStyles.Subtractive) => ToRomanNumerals((int?)num, style);
