人民币小写转大写函数公式：从基础规则到高级应用的全方位指南

'===========================================================
' 函数名：CNY
' 功能：将阿拉伯数字转换为中文大写金额（人民币）
' 作者：AI 助手
' 版本：1.0
'===========================================================
Function CNY(ByVal Amount As Variant) As String
    Dim IntegerPart As String
    Dim DecimalPart As String
    Dim Result As String
    Dim i As Integer
    Dim Num As Long
    Dim Temp As String
    ' 定义数字和单位的数组
    Dim Digits As String
    Digits = "零壹贰叁肆伍陆柒捌玖"
    Dim Units As String
    Units = "拾佰仟"
    Dim BigUnits As String
    BigUnits = "万仟亿兆"
    ' 参数校验
    If IsNull(Amount) Or Amount = "" Then
        CNY = ""
        Exit Function
    End If
    ' 转换为数值类型，防止文本格式干扰
    On Error Resume Next
    Amount = CDbl(Amount)
    If Err.Number <> 0 Then
        CNY = "错误：请输入有效数字"
        Exit Function
    End If
    On Error GoTo 0
    ' 处理负数
    If Amount < 0 Then
        CNY = "负" & CNY(-Amount)
        Exit Function
    End If
    ' 分离整数和小数部分
    Dim IntVal As Long
    Dim DecVal As Double
    IntVal = Int(Abs(Amount))
    DecVal = Abs(Amount) - IntVal
    ' 处理整数部分
    If IntVal = 0 Then
        IntegerPart = "零"
    Else
        IntegerPart = ConvertInteger(IntVal, Digits, Units, BigUnits)
    End If
    ' 处理小数部分（角分）
    Dim Jiao As String
    Dim Fen As String
    Dim DecStr As String
    ' 将小数放大 100 倍取整，避免浮点误差
    DecStr = Format(DecVal  100, "00")
    Jiao = Mid(DecStr, 1, 1)
    Fen = Mid(DecStr, 2, 1)
    ' 只有当小数部分不为 0 时才拼接
    If DecVal > 0 Then
        Result = IntegerPart & "元"
        If Jiao <> "0" Then
            Result = Result & Mid(Digits, Val(Jiao) + 1, 1) & "角"
        Else
            Result = Result & "零"
        End If
        If Fen <> "0" Then
            Result = Result & Mid(Digits, Val(Fen) + 1, 1) & "分"
        End If
    Else
        Result = IntegerPart & "元整"
    End If
    ' 修正首尾的“零”
    Do While Left(Result, 1) = "零" And Len(Result) > 1
        Result = Right(Result, Len(Result) - 1)
    Loop
    If Right(Result, 1) = "零" Then Result = Left(Result, Len(Result) - 1)
    CNY = Result
End Function
' 辅助函数：转换整数部分
Private Function ConvertInteger(ByVal Num As Long, ByVal Digits As String, ByVal Units As String, ByVal BigUnits As String) As String
    Dim Result As String
    Dim LastZero As Boolean
    Dim i As Integer
    Dim Pos As Integer
    Dim DigitChar As String
    If Num = 0 Then
        ConvertInteger = "零"
        Exit Function
    End If
    LastZero = True
    For i = 1 To Len(CStr(Num))
        Dim CurrentDigit As Integer
        CurrentDigit = Val(Mid(CStr(Num), i, 1))
        If CurrentDigit = 0 Then
            If Not LastZero Then
                Result = Result & "零"
                LastZero = True
            End If
        Else
            Result = Result & Mid(Digits, CurrentDigit + 1, 1)
            LastZero = False
            ' 添加单位（个位不加单位）
            If i Mod 4 <> 0 Then
                Result = Result & Mid(Units, 4 - ((i - 1) Mod 4), 1)
            End If
            ' 添加大单位（万、亿）
            If i Mod 4 = 0 And i > 4 Then
                Result = Result & Mid(BigUnits, (i / 4) - 1, 1)
            End If
        End If
    Next i
    ' 去除末尾可能多余的单位
    If Right(Result, 1) = "万" Then Result = Left(Result, Len(Result) - 1) & "整"
    ConvertInteger = Result
End Function