public static BigInt Multiply(BigInt number1, BigInt number2)
{
BigInt result = new BigInt("0", false);
int length = number1.number.Length;
if (number1.number.Length < number2.number.Length)
{
length = number2.number.Length;
}
StringBuilder sbNum1 = new StringBuilder();
for (int i = 0; i < length - number1.Number.Length; i++)
{
sbNum1.Append("0");
}
sbNum1.Append(number1.number);
StringBuilder sbNum2 = new StringBuilder();
for (int i = 0; i < length - number2.Number.Length; i++)
{
sbNum2.Append("0");
}
sbNum2.Append(number2.number);
for (int i = 0; i < length; i++)
{
StringBuilder sb = new StringBuilder();
sb.Clear();
int a = int.Parse(sbNum1[length - 1 - i].ToString());
sb.Append(sbNum2.ToString());
for (int j = 0; j < i; j++)
{
sb.Append("0");
}
for (int k = 0; k < a; k++)
{
result = Sum(result, new BigInt(sb.ToString(), false));
}
}
if (number1.IsNegative != number2.IsNegative)
{
result.IsNegative = true;
}
result = BigInt.TrimZeros(result);
return(result);
}
