public BigInteger Add(
BigInteger value)
{
if (this.sign == 0)
return value;
if (this.sign != value.sign)
{
if (value.sign == 0)
return this;
if (value.sign < 0)
return Subtract(value.Negate());
return value.Subtract(Negate());
}
return AddToMagnitude(value.magnitude);
}
public BigInteger Subtract(
BigInteger n)
{
if (n.sign == 0)
return this;
if (this.sign == 0)
return n.Negate();
if (this.sign != n.sign)
return Add(n.Negate());
int compare = CompareNoLeadingZeroes(0, magnitude, 0, n.magnitude);
if (compare == 0)
return Zero;
BigInteger bigun, lilun;
if (compare < 0)
{
bigun = n;
lilun = this;
}
else
{
bigun = this;
lilun = n;
}
return new BigInteger(this.sign * compare, doSubBigLil(bigun.magnitude, lilun.magnitude), true);
}