toDecimal method

String toDecimal({ int? digits, })

Converts this BigRational to its decimal representation.

digits The number of digits after the decimal point (default is the scale of the BigRational). Returns a string representing the decimal value, with the specified number of digits after the decimal point.

Implementation

String toDecimal({int? digits}) {
  if (digits == null && _inDecimal != null) {
    return _inDecimal!;
  }
  digits ??= scale;
  final BigInt nDive = _truncate;
  final BigInt nReminder = _remainder;
  String intPart = nDive.abs().toString();
  final BigRational remainder = _reduce(nReminder.abs(), denominator);
  final BigRational shiftedRemainder =
      remainder * BigRational._(_ten.pow(digits), _one);
  final BigInt decPart =
      shiftedRemainder.numerator ~/ shiftedRemainder.denominator;
  if (isNegative) {
    intPart = "-$intPart";
  }
  if (decPart == _zero) {
    return intPart;
  }

  String decPartStr = decPart.abs().toString();
  if (decPartStr.length < digits) {
    decPartStr = '0' * (digits - decPartStr.length) + decPartStr;
  }
  if ((shiftedRemainder.numerator % shiftedRemainder.denominator) == _zero) {
    while (decPartStr.endsWith('0')) {
      decPartStr = decPartStr.substring(0, decPartStr.length - 1);
    }
  }

  if (digits < 1) {
    return intPart;
  }

  return '$intPart${decPart < _zero ? '' : '.'}$decPartStr';
}