五、 以不同的字母代表 0 — 9 之间的数字，现有如下等式成立：
    a+bc+def=ghij
编程求出上述条件等式的个数并将所有等式输出。
答：
源程序：
Private Sub Command1_Click()
Dim i, j, m, n As Integer
Dim l As Integer
Dim s As String
l = 0
Text1.Text = ""
For i = 0 To 9
    For j = 10 To 99
        For m = 100 To 999
            n = i + j + m
            s = CStr(i & j & m & n)
            If Len(CStr((n))) = 4 And diff(s) Then
                Text1.Text = Text1.Text & i & "+" & j & "+" & m & "=" & n & vbCrLf
                l = l + 1
            End If
        Next m
    Next j
Next i
Text2.Text = "查找到满足条件的等式个数为：" & l
End Sub

Private Function diff(ByVal s As String) As Boolean
Dim i, j As Integer
Dim a() As Integer
i = Len(s)
diff = True
ReDim a(i)
For j = 1 To i
    a(j) = Int(Mid(s, j, 1))
Next j
For j = 1 To i - 1
    For k = j + 1 To i
        If a(j) = a(k) Then
            diff = False
            Exit Function
        End If
    Next k
Next j
End Function

六、 下面的竖式表示乘法运算，其中 “ * ” 只能用素数 2 ， 3 ， 5 ， 7 代替，因此称为素数乘法竖式。
                * * *
            ×     * *
         --------------------
                 * * * *
              * * * *
          -------------------
               * * * * *
答：
源程序：
Option Base 1
Dim a(4) As Integer
Private Sub Command1_Click()
Dim i, j, k As Integer
Dim m As Long, n As Long, p As Long
Dim arr() As Long
Dim brr() As Long
Dim idx1 As Integer
Dim idx2 As Integer
idx1 = 0
idx2 = 0
a(1) = 2
a(2) = 3
a(3) = 5
a(4) = 7
For i = 1 To 4
    For j = 1 To 4
        idx1 = idx1 + 1
        ReDim Preserve brr(idx1)
        brr(idx1) = a(i) * 10 + a(j)
        For k = 1 To 4
            idx2 = idx2 + 1
            ReDim Preserve arr(idx2)
            arr(idx2) = a(i) * 100 + a(j) * 10 + a(k)
        Next k
    Next j
Next i
For i = 1 To UBound(arr)
    For j = 1 To UBound(brr)
        m = arr(i) * (brr(j) \ 10)
        n = arr(i) * (brr(j) Mod 10)
        p = arr(i) * brr(j)
        If pd(m) And pd(n) And pd(p) Then
            Text1.Text = arr(i) \ 100
            Text2.Text = arr(i) \ 10 Mod 10
            Text3.Text = arr(i) Mod 10
            Text4.Text = brr(j) \ 10
            Text5.Text = brr(j) Mod 10
            Text6.Text = n \ 1000
            Text7.Text = n \ 100 Mod 10
            Text8.Text = n \ 10 Mod 10
            Text9.Text = n Mod 10
            Text10.Text = m \ 1000
            Text11.Text = m \ 100 Mod 10
            Text12.Text = m \ 10 Mod 10
            Text13.Text = m Mod 10
            Text14.Text = p \ 10000
            Text15.Text = p \ 1000 Mod 10
            Text16.Text = p \ 100 Mod 10
            Text17.Text = p \ 10 Mod 10
            Text18.Text = p Mod 10
        End If
    Next j
Next i

                           
End Sub
Private Function pd(ByVal x As Long) As Boolean
Dim b() As Integer
Dim l As Integer
l = 0
ReDim b(Len(CStr(x)))
For i = 1 To Len(CStr(x))
    b(i) = Int(Mid(CStr(x), i, 1))
    For j = 1 To 4
        If b(i) = a(j) Then
            l = l + 1
            'pd = True
            Exit For
        End If
    Next j
    If j > 4 Then pd = False: Exit Function
Next i
If l = Len(CStr(x)) Then
    pd = True
Else
    pd = False
End If
End Function

Private Sub Command2_Click()
Text1.Text = ""
Text2.Text = ""
Text3.Text = ""
Text4.Text = ""
Text5.Text = ""
Text6.Text = ""
Text7.Text = ""
Text8.Text = ""
Text9.Text = ""
Text10.Text = ""
Text11.Text = ""
Text12.Text = ""
Text13.Text = ""
Text14.Text = ""
Text15.Text = ""
Text16.Text = ""
Text17.Text = ""
Text18.Text = ""
End Sub