private static BigPointNumber Multiply(BigPointNumber a, BigPointNumber b)
{
var retValue = Zero;
for (var i = 0; i < a.Size; i++)
{
for (int j = 0, carry = 0; (j < b.Size) || (carry > 0); j++)
{
var cur = retValue.GetByte(i + j) + a.GetByte(i) * b.GetByte(j) + carry;
retValue.SetByte(i + j, (byte)(cur % 10));
carry = cur / 10;
}
}
retValue.Sign = a.Sign == b.Sign ? Sign.Plus : Sign.Minus;
int delta = 0;
delta += a.PointPosition != -1 ? a.SizeAfterPoint : 0;
delta += b.PointPosition != -1 ? b.SizeAfterPoint : 0;
retValue.PointPosition = retValue.digits.Count - delta;
if (retValue.PointPosition == retValue.digits.Count)
{
retValue.PointPosition = -1;
}
retValue.RemoveNulls();
return(retValue);
}
private static BigPointNumber Substract(BigPointNumber a, BigPointNumber b)
{
BigPointNumber tmp_a = a;
BigPointNumber tmp_b = b;
var digits = new List <byte>();
BigPointNumber max = Zero;
BigPointNumber min = Zero;
//сравниваем числа игнорируя знак
var compare = Comparison(tmp_a, tmp_b, ignoreSign: true);
switch (compare)
{
case -1:
min = tmp_a;
max = tmp_b;
break;
case 0:
//если числа равны возвращаем 0
return(Zero);
case 1:
min = tmp_b;
max = tmp_a;
break;
}
//из большего вычитаем меньшее
EqualizationDigitsCount(ref tmp_a, ref tmp_b);
var t = 0;
for (var i = 0; i < tmp_a.Size; i++)
{
var s = max.GetByte(i) - min.GetByte(i) - t;
if (s < 0)
{
s += 10;
t = 1;
}
else
{
t = 0;
}
digits.Add((byte)s);
}
int tmp_PointPos = tmp_a.PointPosition > tmp_b.PointPosition ? tmp_a.PointPosition : tmp_b.PointPosition;
BigPointNumber result = new BigPointNumber(digits, max.Sign, tmp_PointPos);
result.RemoveNulls();
return(new BigPointNumber(digits, max.Sign, tmp_PointPos));
}
private static int CompareDigits(BigPointNumber a, BigPointNumber b)
{
BigPointNumber tmp_a = a;
BigPointNumber tmp_b = b;
EqualizationDigitsCount(ref tmp_a, ref tmp_b);
for (var i = tmp_a.Size; i >= 0; i--)
{
if (tmp_a.GetByte(i) < tmp_b.GetByte(i))
{
return(-1);
}
else if (tmp_a.GetByte(i) > tmp_b.GetByte(i))
{
return(1);
}
}
return(0);
}
private static BigPointNumber Add(BigPointNumber a, BigPointNumber b)
{
BigPointNumber tmp_a = a;
BigPointNumber tmp_b = b;
EqualizationDigitsCount(ref tmp_a, ref tmp_b);
var digits = new List <byte>();
byte t = 0;
for (int i = 0; i < tmp_a.Size; i++)
{
byte sum = (byte)(a.GetByte(i) + b.GetByte(i) + t);
if (sum > 10)
{
sum -= 10;
t = 1;
}
else
{
t = 0;
}
digits.Add(sum);
}
if (t > 0)
{
digits.Add(t);
}
int tmp_PointPos = tmp_a.PointPosition > tmp_b.PointPosition ? tmp_a.PointPosition : tmp_b.PointPosition;
return(new BigPointNumber(digits, tmp_a.Sign, tmp_PointPos));
}