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至顶网›软件频道 ›基础软件›200的阶乘即200!是多少?一个简陋的大数加、乘方法

200的阶乘即200!是多少?一个简陋的大数加、乘方法

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200的阶乘即200!是多少?一个简陋的大数加、乘方法

作者：水如烟 来源：CSDN 2007年12月19日

关键字： 乘 大数 简陋

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首先列出结果，共375位：
200 ,375 ,7886578673647905035523632139321850622951359776871732632947425332443594499634033429203042840119846239041772121389196
38830257642790242637105061926624952829931113462857270763317237396988943922445621451664240254033291864131227428294853
27752424240757390324032125740557956866022603190417032406235170085879617892222278962370389737472000000000000000000000
0000000000000000000000000000

说它简陋，一是算法欠妥（不懂），二是没发挥计算机的计算能力（线程和服务）。只是，管它黑猫白猫，抓到老鼠就是了。
它的应用还是蛮大的，可以算递归数列，特别将它与数据库结合后，可以得到数表。现在我只是简单的算算阶乘。在100之内，它还是蛮快的。可能与我的计算机有关。300之后，就慢多了，不过数据位数已大于615位了。

测试：

 

Public Class Form1

    Dim a As New UnitString
    Dim b As New UnitString
    Dim s As UnitString
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        a.Value = "1"
        For i As Integer = 1 To 300
            b.Value = i.ToString
            a = a * b
        Next
        Me.RichTextBox1.AppendText(String.Format("{0,-4},{1,-4},{2}", 300, a.Length, a.Value) & vbCrLf)
    End Sub

End Class


就两个文件。注释没写，不好意思。
UnitChar.vb

 

Public Class UnitChar
    Private gCarry As Integer = 0

    ''' <summary>
    ''' 最后一次运算的进位
    ''' </summary>
    ''' <remarks>仅保存最后一次运算</remarks>
    Public ReadOnly Property Carry() As Integer
        Get
            Return gCarry
        End Get
    End Property

    Private gValue As Char = "0"c

    ''' <summary>
    ''' 值
    ''' </summary>
    Public Property Value() As Char
        Get
            Return gValue
        End Get
        Set(ByVal value As Char)
            gValue = value
        End Set
    End Property

    ''' <summary>
    ''' 副本
    ''' </summary>
    Public Function Clone() As UnitChar
        Dim mResult As New UnitChar
        With mResult
            .gValue = Me.gValue
            .gCarry = Me.gCarry
        End With
        Return mResult
    End Function

    ''' <summary>
    ''' 整数
    ''' </summary>
    Public Function ToInteger() As Integer
        Return CType(gValue.ToString, Integer)
    End Function


    ' 进位清零
    Private Sub ClearCarry()
        gCarry = 0
    End Sub

    Public Sub Add(ByVal unit As UnitChar)
        Me.ClearCarry()

        Dim mAddResult() As Char
        mAddResult = (Me.ToInteger + unit.ToInteger).ToString.ToCharArray

        If mAddResult.Length = 2 Then
            Me.gCarry = CType(mAddResult(0).ToString, Integer)
            Me.gValue = mAddResult(1)
        Else
            Me.gValue = mAddResult(0)
        End If


    End Sub

    Public Sub Multiply(ByVal unit As UnitChar)
        Me.ClearCarry()

        Dim mAddResult() As Char
        mAddResult = (Me.ToInteger * unit.ToInteger).ToString.ToCharArray

        If mAddResult.Length = 2 Then
            Me.gCarry = CType(mAddResult(0).ToString, Integer)
            Me.gValue = mAddResult(1)
        Else
            Me.gValue = mAddResult(0)
        End If
    End Sub


    Public Shared Operator +(ByVal a As UnitChar, ByVal b As UnitChar) As UnitChar
        Dim mResult As UnitChar = a.Clone

        mResult.Add(b)

        Return mResult
    End Operator

    Public Shared Operator *(ByVal a As UnitChar, ByVal b As UnitChar) As UnitChar
        Dim mResult As UnitChar = a.Clone

        mResult.Multiply(b)

        Return mResult
    End Operator

End Class

UnitString.vb

Public Class UnitString

    '进位
    Protected gCarry As Integer = 0

    Protected gOriginalValue As String
    Protected gCurrentUniChars() As UnitChar
    Protected gLength As Integer

    Public ReadOnly Property Length() As Integer
        Get
            Return gLength
        End Get
    End Property

    Private gValue As String = "0"

    ''' <summary>
    ''' 值
    ''' </summary>
    Public Property Value() As String
        Get
            Dim mBuilder As New System.Text.StringBuilder

            If gCarry > 0 Then
                mBuilder.Append(gCarry.ToString)
            End If

            For i As Integer = 0 To Me.gLength - 1
                mBuilder.Append(Me.gCurrentUniChars(i).Value)
            Next

            Return mBuilder.ToString
        End Get
        Set(ByVal value As String)
            Me.gValue = value
            Me.gOriginalValue = value
            Initialize()
        End Set
    End Property

    Public ReadOnly Property NewUnitString() As UnitString
        Get
            Dim mResult As New UnitString

            mResult.Value = Me.Value

            Return mResult
        End Get
    End Property

    Private Sub Initialize()
        Me.ClearCarry()
        Me.gCurrentUniChars = ToUnitChars(Me.gOriginalValue)
        Me.gLength = Me.gCurrentUniChars.Length
    End Sub

    Private Function ToUnitChars(ByVal value As String) As UnitChar()
        Dim mChars() As Char = value.ToCharArray
        Dim mResult(mChars.Length - 1) As UnitChar

        For i As Integer = 0 To mChars.Length - 1
            mResult(i) = New UnitChar
            mResult(i).Value = mChars(i)
        Next

        Return mResult
    End Function

    ''' <summary>
    ''' 副本
    ''' </summary>
    Public Function Clone() As UnitString
        Dim mResult As New UnitString
        With mResult
            .Value = Me.Value
        End With
        Return mResult
    End Function


    ' 进位清零
    Private Sub ClearCarry()
        gCarry = 0
    End Sub

    Public Sub Add(ByVal unit As UnitString)

        Dim mValue1 As UnitString
        Dim mValue2 As UnitString

        If Me.Length >= unit.Length Then
            mValue1 = Me
            mValue2 = unit
        Else
            mValue1 = unit
            mValue2 = Me
        End If

        Dim tmpUnitChars() As UnitChar = Me.ToUnitChars(mValue2.Value)
        For i As Integer = mValue2.Length - 1 To 0 Step -1
            mValue1.AddChar(tmpUnitChars(mValue2.Length - i - 1), i)
        Next

        Me.Value = mValue1.Value
    End Sub

    Public Sub Multiply(ByVal unit As UnitString)

        Dim mValue1 As UnitString
        Dim mValue2 As UnitString

        If Me.Length >= unit.Length Then
            mValue1 = Me.Clone
            mValue2 = unit.Clone
        Else
            mValue1 = unit.Clone
            mValue2 = Me.Clone
        End If

        Dim tmpUnitStrings(mValue2.Length - 1) As UnitString

        Dim tmpUnitChars() As UnitChar = Me.ToUnitChars(mValue2.Value)
        For i As Integer = 0 To mValue2.Length - 1
            tmpUnitStrings(i) = mValue1.Clone
            tmpUnitStrings(i).MultiplyChar(tmpUnitChars(i))
            If tmpUnitStrings(i).gCarry > 0 Then
                tmpUnitStrings(i) = tmpUnitStrings(i).NewUnitString
            End If

        Next

        Dim mResult As New UnitString
        Dim tmp As UnitString
        For i As Integer = 0 To mValue2.Length - 1
            mResult = mResult.NewUnitString

            tmp = New UnitString
            tmp.Value = tmpUnitStrings(i).Value & New String("0"c, mValue2.Length - i - 1)
            mResult.Add(tmp)
        Next

        Me.Value = mResult.Value

    End Sub

    Public Shared Operator +(ByVal a As UnitString, ByVal b As UnitString) As UnitString
        Dim mResult As UnitString = a.Clone

        mResult.Add(b)

        Return mResult
    End Operator

    Public Shared Operator *(ByVal a As UnitString, ByVal b As UnitString) As UnitString
        Dim mResult As UnitString = a.Clone

        mResult.Multiply(b)

        Return mResult
    End Operator

    Protected Overridable Sub AddChar(ByVal unit As UnitChar, ByVal OperateDigit As Integer)
        Dim mCurrentUnitChar As UnitChar = Me.gCurrentUniChars(Me.gLength - OperateDigit - 1)
        mCurrentUnitChar.Add(unit)
        If mCurrentUnitChar.Carry > 0 Then
            If Me.gLength - OperateDigit - 1 = 0 Then
                Me.gCarry += mCurrentUnitChar.Carry
            Else
                Dim tmp As New UnitChar
                tmp.Value = CType(mCurrentUnitChar.Carry.ToString, Char)
                AddChar(tmp, OperateDigit + 1)
            End If
        End If
    End Sub

    Protected Overridable Sub MultiplyChar(ByVal unit As UnitChar)
        For i As Integer = Me.gLength - 1 To 0 Step -1
            MultiplyCharSingle(unit, i)
        Next
    End Sub

    Protected Overridable Sub MultiplyCharSingle(ByVal unit As UnitChar, ByVal OperateDigit As Integer)
        Dim mCurrentUnitChar As UnitChar = Me.gCurrentUniChars(Me.gLength - OperateDigit - 1)
        mCurrentUnitChar.Multiply(unit)
        If mCurrentUnitChar.Carry > 0 Then
            If Me.gLength - OperateDigit - 1 = 0 Then
                Me.gCarry += mCurrentUnitChar.Carry
            Else
                Dim tmp As New UnitChar
                tmp.Value = CType(mCurrentUnitChar.Carry.ToString, Char)
                AddChar(tmp, OperateDigit + 1)
            End If
        End If
    End Sub
End Class

一并列出测试加、乘：

Public Class Form1

    Dim a As New UnitString
    Dim b As New UnitString
    Dim s As UnitString
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        a.Value = New String("9"c, CInt(Math.Pow(2, 10))) '相加超过14就不行了，相乘没试过。
        b.Value = New String("9"c, CInt(Math.Pow(2, 10)))
        s = a + b
        Me.RichTextBox1.AppendText(a.Value & vbCrLf)
        Me.RichTextBox1.AppendText("+" & vbCrLf)
        Me.RichTextBox1.AppendText(b.Value & vbCrLf)
        Me.RichTextBox1.AppendText("=" & vbCrLf)
        Me.RichTextBox1.AppendText(s.Value & vbCrLf)
        s = a * b
        Me.RichTextBox1.AppendText(a.Value & vbCrLf)
        Me.RichTextBox1.AppendText("*" & vbCrLf)
        Me.RichTextBox1.AppendText(b.Value & vbCrLf)
        Me.RichTextBox1.AppendText("=" & vbCrLf)
        Me.RichTextBox1.AppendText(s.Value & vbCrLf)
    End Sub

End Class

结果：

99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
999999999999999999999999999999999999999999999999999999999999999999999999
+
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
999999999999999999999999999999999999999999999999999999999999999999999999
=
19999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
9999999999999999999999999999999999999999999999999999999999999999999999998

99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
999999999999999999999999999999999999999999999999999999999999999999999999
*
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
999999999999999999999999999999999999999999999999999999999999999999999999
=
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999999
99999999999999999999999999999999999999999999999999999999999999999999999800000000000000000000000000000000000000000000000
00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000
0000000000000000000000001

 

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