public static IEnumerable <BigInteger> ToDigitRotations(this BigInteger input)
{
var digits = input.ToDigits().ToList();
var result = digits
.Concat(digits);
var movingWindow = result
.ToMovingWindow(digits.Count)
.Take(digits.Count);
return(movingWindow
.Select(rotation => rotation.FromDigits()));
}
public static BigInteger ReverseDigits(this BigInteger input, int baseToUse = 10) => input.ToDigits(baseToUse).Reverse().FromDigits(baseToUse);
/// <summary>
/// Writes the given number in words. Currently only valid between 1 and 1000 (inclusive)
/// </summary>
/// <param name="toConvert"></param>
/// <returns></returns>
public static string ToWords(this BigInteger toConvert)
{
var words = new StringBuilder();
Action <string> add = (input) => words.Append(input);
Action addHundred = () => add(" hundred ");
Action addAnd = () => add(" and ");
Action <BigInteger> basicDigitToWord = (BigInteger digit)
=>
{
switch ((int)digit)
{
case 0:
break;
case 1:
add(" one ");
break;
case 2:
add(" two ");
break;
case 3:
add(" three ");
break;
case 4:
add(" four ");
break;
case 5:
add(" five ");
break;
case 6:
add(" six ");
break;
case 7:
add(" seven ");
break;
case 8:
add(" eight ");
break;
case 9:
add(" nine ");
break;
default:
throw new IndexOutOfRangeException($"digits only, please; value provided was ${digit}");
}
};
Action <BigInteger> teensDigitToWords = (BigInteger onesPlace) =>
{
switch ((int)onesPlace)
{
case 0:
add(" ten ");
break;
case 1:
add(" eleven ");
break;
case 2:
add(" twelve ");
break;
case 3:
add(" thirteen ");
break;
case 4:
add(" fourteen ");
break;
case 5:
add(" fifteen ");
break;
case 6:
add(" sixteen ");
break;
case 7:
add(" seventeen ");
break;
case 8:
add(" eighteen ");
break;
case 9:
add(" nineteen ");
break;
default:
throw new IndexOutOfRangeException($"digits only, please; value provided was ${onesPlace}");
}
};
Action <BigInteger, BigInteger> tensDigitToWord = (BigInteger digit, BigInteger onesDigit) =>
{
Action addOnesDigit = () => basicDigitToWord(onesDigit);
switch ((int)digit)
{
case 0:
addOnesDigit();
break;
case 1:
teensDigitToWords(onesDigit);
break;
case 2:
add(" twenty ");
addOnesDigit();
break;
case 3:
add(" thirty ");
addOnesDigit();
break;
case 4:
add(" forty ");
addOnesDigit();
break;
case 5:
add(" fifty ");
addOnesDigit();
break;
case 6:
add(" sixty ");
addOnesDigit();
break;
case 7:
add(" seventy ");
addOnesDigit();
break;
case 8:
add(" eighty ");
addOnesDigit();
break;
case 9:
add(" ninety ");
addOnesDigit();
break;
default:
throw new IndexOutOfRangeException($"digits only, please; value provided was ${digit}");
}
};
Action <BigInteger, BigInteger, BigInteger> addDigitsToWords = (BigInteger hundreds, BigInteger tens, BigInteger ones)
=>
{
if (hundreds > 0)
{
basicDigitToWord(hundreds);
add(" hundred ");
if (!(tens == 0 && ones == 0))
{
add(" and ");
}
}
tensDigitToWord(tens, ones);
};
var digits = toConvert.ToDigits().ToList();
if (digits.Count() > 3)
{
add("one thousand");
}
else
{
if (digits.Count == 3)
{
addDigitsToWords(digits[2], digits[1], digits[0]);
}
if (digits.Count == 2)
{
tensDigitToWord(digits[1], digits[0]);
}
if (digits.Count == 1)
{
basicDigitToWord(digits[0]);
}
}
return(words.ToString());
}
public static bool IsTruncatable(this BigInteger prime, PrimeService primeService)
=> prime.ToDigits()
.ToArray()
.All(
((BigInteger[] digitArray, int index)i)
public static bool HasRepeatedDigits(this BigInteger num) => num .ToDigits() .GroupBy(term => term) .Any(group => group.Count() > 1);
