public VeryLong Subtract(VeryLong subtrahend)
{
int minuendDecimalPlaces = GetDecimalPlaces();
int subtrahendDecimalPlaces = subtrahend.GetDecimalPlaces();
int decimalPlaces = Math.Max(minuendDecimalPlaces, subtrahendDecimalPlaces);
FillUpDecimalPlacesWithZero(decimalPlaces);
subtrahend.FillUpDecimalPlacesWithZero(decimalPlaces);
string result = "";
int diff = 0;
int borrow = 0;
int currentLastDigit = 0;
int currentLastDigitSubtrahend = 0;
int i = 0;
if (!IsLargerOrEqual(subtrahend))
{
// swap: minuend is smaller than subtrahend --> result is negative
VeryLong newMinuend = subtrahend;
VeryLong newSubtrahend = new VeryLong(ToString());
VeryLong difference = newMinuend.Subtract(newSubtrahend);
return(new VeryLong("-" + difference.ToString()));
}
while (Length() > i || subtrahend.Length() > i || borrow != 0)
{
if (GetLastDigit(i) == ".")
{
result = result.Insert(0, ".");
i++;
continue;
}
currentLastDigit = int.Parse(GetLastDigit(i));
currentLastDigitSubtrahend = int.Parse(subtrahend.GetLastDigit(i));
diff = currentLastDigit - currentLastDigitSubtrahend - borrow;
if (diff < 0)
{
borrow = 1;
diff += 10;
}
else
{
borrow = 0;
}
result = result.Insert(0, diff.ToString());
i++;
}
result = RemoveLeadingZeros(result);
return(new VeryLong(result));
}
public VeryLong Multiply(VeryLong other)
{
int numberDecimalPlaces = GetDecimalPlaces();
int numberDecimalPlacesOther = other.GetDecimalPlaces();
int resultDecialPlaces = numberDecimalPlaces + numberDecimalPlacesOther;
other = RemoveDecimalPlaces(other);
string integerStringCopy = _integerString;
_integerString = _integerString.Replace(".", "");
List <string> multiplicationResults = new List <string>();
string multiplicationResult = GetZeros(1);
int currentLastDigit = 0;
int currentLastDigitOther = 0;
int resultDigit = 0;
int behalte = 0;
int mult = 0;
int indexOther = 0;
int index = 0;
while (Length() > index)
{
indexOther = 0;
behalte = 0;
multiplicationResult = GetZeros(index);
while (other.Length() > indexOther || behalte != 0)
{
currentLastDigit = int.Parse(GetLastDigit(index));
currentLastDigitOther = int.Parse(other.GetLastDigit(indexOther));
mult = currentLastDigit * currentLastDigitOther + behalte;
behalte = mult / 10;
resultDigit = mult % 10;
multiplicationResult = multiplicationResult.Insert(0, resultDigit.ToString());
indexOther++;
}
index++;
multiplicationResults.Add(multiplicationResult);
}
VeryLong mainResult = VeryLong.AddSummands(multiplicationResults);
mainResult.SetDecimalPlaces(resultDecialPlaces);
mainResult.RemoveLeadingZeros();
_integerString = integerStringCopy;
return(mainResult);
}
public VeryLong DivideBy(VeryLong divisor, int numberOfDigits)
{
int numberDecimalPlacesDivisor = divisor.GetDecimalPlaces();
divisor = RemoveDecimalPlaces(divisor);
FillUpDecimalPlacesWithZero(numberOfDigits + numberDecimalPlacesDivisor);
string dividendString = "";
string divisorString = divisor.ToString();
string quotientDigit = "";
string quotient = "";
string mult = "";
string diff = "";
for (int i = 0; i < Length(); i++)
{
if (GetFirstDigit(i) == ".")
{
quotient += ".";
continue;
}
dividendString += GetFirstDigit(i);
dividendString = VeryLong.RemoveLeadingZeros(dividendString);
quotientDigit = DivideSimple(dividendString, divisorString);
quotient += quotientDigit;
mult = (new VeryLong(quotientDigit).Multiply(new VeryLong(divisorString))).ToString();
diff = (new VeryLong(dividendString).Subtract(new VeryLong(mult))).ToString();
dividendString = diff;
}
VeryLong quotientResult = new VeryLong(quotient);
int resultDecimalPlaces = quotientResult.GetDecimalPlaces();
quotientResult = RemoveDecimalPlaces(quotientResult);
quotientResult.SetDecimalPlaces(resultDecimalPlaces - numberDecimalPlacesDivisor);
quotientResult.RemoveLeadingZeros();
quotientResult.LimitPrecisionTo(numberOfDigits);
return(quotientResult);
}
public VeryLong Add(VeryLong other)
{
int summand1DecimalPlaces = GetDecimalPlaces();
int summand2DecimalPlaces = other.GetDecimalPlaces();
int decimalPlaces = Math.Max(summand1DecimalPlaces, summand2DecimalPlaces);
FillUpDecimalPlacesWithZero(decimalPlaces);
other.FillUpDecimalPlacesWithZero(decimalPlaces);
string result = "";
int sum = 0;
int behalte = 0;
int resultDigit = 0;
int currentLastDigit = 0;
int currentLastDigitOther = 0;
int i = 0;
while (Length() > i || other.Length() > i || behalte != 0)
{
if (GetLastDigit(i) == ".")
{
result = result.Insert(0, ".");
i++;
continue;
}
currentLastDigit = int.Parse(GetLastDigit(i));
currentLastDigitOther = int.Parse(other.GetLastDigit(i));
sum = currentLastDigit + currentLastDigitOther + behalte;
behalte = sum / 10;
resultDigit = sum % 10;
result = result.Insert(0, resultDigit.ToString());
i++;
}
return(new VeryLong(result));
}
