public static BigInt operator +(BigInt a, BigInt b)
{
BigInt sum = new BigInt(0);
BigInt aCopy = new BigInt(a);
BigInt bCopy = new BigInt(b);
sum.Sign = 1;
sum.number.Clear(); // знак +, нет никаких элементов
//выравниваем числа по длине
int sizeA = aCopy.number.Count, sizeB = bCopy.number.Count;
if (sizeA < sizeB)
{
for (int i = 0; i < sizeB - sizeA; i++)
{
aCopy.number.Insert(0, 0);
}
}
else if (sizeA > sizeB)
{
for (int i = 0; i < -(sizeB - sizeA); i++)
{
bCopy.number.Insert(0, 0);
}
}
sizeA = aCopy.number.Count;
if (aCopy.Sign * bCopy.Sign == 1) // оба числа одного знака
{
int k = 0, w;
for (int i = sizeA - 1; i >= 0; i--)
{
w = Mod(aCopy.number[i] + bCopy.number[i] + k, 10);
k = Div(aCopy.number[i] + bCopy.number[i] + k, 10);
sum.number.Insert(0, w);
}
if (k > 0) // k=0 или k=1
{
sum.number.Insert(0, k);
}
if (aCopy.Sign == -1)
{
sum.Sign = -1;
}
}
else
{
BigInt bigger;
BigInt smaller;
if (Abs(aCopy) >= Abs(bCopy))
{
sum.Sign = aCopy.Sign;
bigger = Abs(aCopy);
smaller = Abs(bCopy);
}
else
{
sum.Sign = bCopy.Sign;
bigger = Abs(bCopy);
smaller = Abs(aCopy);
}
{
int k = 0, w;
for (int i = sizeA - 1; i >= 0; i--)
{
w = Mod(bigger.number[i] - smaller.number[i] + k, 10);
k = Div(bigger.number[i] - smaller.number[i] + k, 10);
sum.number.Insert(0, w);
}
}
}
sum.RemoveBeginZeros();
return(sum);
}