/// <summary>开方</summary>
static internal BigNumber Sqrt(BigNumber value, int precision)
{
if (!value.IsPlus)
{
throw new ExpressionException("只有正数才有开平方运算");
}
List <int> div = new List <int>();
int index = 0;
int resultIntCount = (value.IntPart.Count + 1) / 2;
List <int> result = GetFirstDiv(value, ref div, ref index);
div = FirstTry(result, div);
div.AddRange(GetNewTwoDiv(value, ref index));
BigCalculate.RemoveStartZero(div);
//考虑精度的计算
while (true)
{
div = TryDiv(div, result);
if (result.Count - resultIntCount >= precision)
{
break;
}
div.AddRange(GetNewTwoDiv(value, ref index));
BigCalculate.RemoveStartZero(div);
}
return(new BigNumber(result.GetRange(0, resultIntCount), result.GetRange(resultIntCount, result.Count - resultIntCount), true));
}
/// <summary>返回0.00001这样的数小数点后、有效数前有几个零</summary>
internal int GetPrecision(int value)
{
if (value == 0)
{
BigCalculate.RemoveStartZero(IntPart);
if (IntPart.Count == 1 && IntPart[0] == 0)
{
if (DecimalPart.Count == 0)
{
return(0);
}
for (int i = 0; i < DecimalPart.Count; i++)
{
if (DecimalPart[i] != 0)
{
return(i);
}
}
return(DecimalPart.Count);
}
return(0);
}
else
{
if (IntPart.Count == 1 && IntPart[0] == 1)
{
if (DecimalPart.Count == 0)
{
return(0);
}
for (int i = 0; i < DecimalPart.Count; i++)
{
if (DecimalPart[i] != 0)
{
return(i);
}
}
return(DecimalPart.Count);
}
return(0);
}
}
/// <summary>识别出一个大数，返回值为这个是不是正数</summary>
public static bool GetBigNumber(string text, List <int> intPart, List <int> decimalPart)
{
ValidateNumber(text);
bool isPlus = true;
int haveSym = 0;
if (text[0] == '-')
{
isPlus = false;
haveSym = 1;
}
else if (text[0] == '+')
{
haveSym = 1;
}
int pointIndex = text.IndexOf('.');
//有小数点
if (pointIndex != -1)
{
int i = 0;
if ((pointIndex - haveSym) % BigNumber.OneCount != 0)
{
intPart.Add(Convert.ToInt32(text.Substring(haveSym, (pointIndex - haveSym) % BigNumber.OneCount)));
}
for (; i < (pointIndex - haveSym) / BigNumber.OneCount; i++)
{
intPart.Add(Convert.ToInt32(text.Substring(haveSym + i * BigNumber.OneCount + (pointIndex - haveSym) % BigNumber.OneCount, BigNumber.OneCount)));
}
i = pointIndex + 1;
while (i < text.Length)
{
if (text.Length - i >= BigNumber.OneCount)
{
decimalPart.Add(Convert.ToInt32(text.Substring(i, BigNumber.OneCount)));
}
else
{
decimalPart.Add(Convert.ToInt32(text.Substring(i, (text.Length - i) % BigNumber.OneCount).PadRight(BigNumber.OneCount, '0')));
}
i += BigNumber.OneCount;
}
}
//没有小数点
else
{
if ((text.Length - haveSym) % BigNumber.OneCount != 0)
{
intPart.Add(Convert.ToInt32(text.Substring(haveSym, (text.Length - haveSym) % BigNumber.OneCount)));
}
for (int i = 0; i < (text.Length - haveSym) / BigNumber.OneCount; i++)
{
intPart.Add(Convert.ToInt32(text.Substring(haveSym + i * BigNumber.OneCount + (text.Length - haveSym) % BigNumber.OneCount, BigNumber.OneCount)));
}
}
BigCalculate.RemoveStartZero(intPart);
if (intPart.Count == 0)
{
intPart.Add(0);
}
return(isPlus);
}
static int ComparePlus(BigNumber one, BigNumber two)
{
BigCalculate.RemoveStartZero(one.IntPart);
BigCalculate.RemoveStartZero(two.IntPart);
int minDecimalLength = one.DecimalPart.Count < two.DecimalPart.Count ? one.DecimalPart.Count : two.DecimalPart.Count;
//通过正数的长短比较
if (one.IntPart.Count > two.IntPart.Count)
{
return(1);
}
else if (one.IntPart.Count < two.IntPart.Count)
{
return(-1);
}
else
{
//从最高位依次比较
for (int i = 0; i < one.IntPart.Count; i++)
{
if (one.IntPart[i] > two.IntPart[i])
{
return(1);
}
else if (one.IntPart[i] < two.IntPart[i])
{
return(-1);
}
}
//比较小数部分，行判断是否有小数位
if (one.DecimalPart.Count == 0 && two.DecimalPart.Count != 0)
{
return(-1);
}
else if (one.DecimalPart.Count != 0 && two.DecimalPart.Count == 0)
{
return(1);
}
else if (one.DecimalPart.Count == 0 && two.DecimalPart.Count == 0)
{
return(0);
}
else
{
for (int i = 0; i < minDecimalLength; i++)
{
if (one.DecimalPart[i] > two.DecimalPart[i])
{
return(1);
}
else if (one.DecimalPart[i] < two.DecimalPart[i])
{
return(-1);
}
}
if (one.DecimalPart.Count > two.DecimalPart.Count)
{
return(1);
}
else if (one.DecimalPart.Count < two.DecimalPart.Count)
{
return(-1);
}
}
return(0);
}
}