public static string ToRoman(int number) { if ((number 3999)) throw new ArgumentOutOfRangeException("insert value betwheen 1 and 3999"); if (number = 1000) return "M" + ToRoman(number - 1000); if (number >= 900) return "CM" + ToRoman(number - 900); if (number >= 500) return "D" + ToRoman(number - 500); if (number >= 400) return "CD" + ToRoman(number - 400); if (number >= 100) return "C" + ToRoman(number - 100); if (number >= 90) return "XC" + ToRoman(number - 90); if (number >= 50) return "L" + ToRoman(number - 50); if (number >= 40) return "XL" + ToRoman(number - 40); if (number >= 10) return "X" + ToRoman(number - 10); if (number >= 9) return "IX" + ToRoman(number - 9); if (number >= 5) return "V" + ToRoman(number - 5); if (number >= 4) return "IV" + ToRoman(number - 4); if (number >= 1) return "I" + ToRoman(number - 1); throw new ArgumentOutOfRangeException("something bad happened"); }