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1、算法说明
1) 十进制正整数m转换为R（2－16）进制的字符串。
思路： 将m不断除r取余数，直到商为0，将余数反序即得到结果。
算法实现：
Private Function Tran(ByVal m As Integer, ByVal r As Integer) As String
Dim StrDtoR As String, n As Integer
Do While m <> o
n = m Mod r
m = m \ r
If n > 9 Then
StrDtoR = Chr(65 + n - 10) & StrDtoR
Else
StrDtoR = n & StrDtoR
End If
Loop
Tran = StrDtoR
End Function
2) R（2－16）进制字符串转换为十进制正整数。
思路：R进制数每位数字乘以权值之和即为十进制数。
算法实现：
Private Function Tran(ByVal s As String, ByVal r As Integer) As integer
Dim n As Integer, dec As Integer
s = UCase(Trim(s))
For i% = 1 To Len(s)
If Mid(s, i, 1) >= "A" Then
n = Asc(Mid(s, i, 1)) - Asc("A") + 10
Else
n = Val(Mid(s, i, 1))
End If
dec = dec + n * r ^ (Len(s) - i)
Next i
Tran = dec
End Function
解题技巧
进制转化的原理要清楚,同时编写代码时候要留意16进制中的A－F字符的处理。
2、实战练习
1) 补充代码（2002秋二（9））
本程序是把给定的二进制整数转换为八进制整数。
Private Sub Command1_Click()
Dim a As String, b As String, c As String
Dim L As Integer, m As Integer, n As Integer
a = InputBox("请输入一个二进制数", "输入框")
（1）
a = String(L, "0") & a
（2）
For m = 1 To n / 3
b = Mid(a, 3 * m - 2, 3)
（3）
Next m
Text1.Text = c
End Sub
Private Function zh(s As String) As String
Dim i As Integer, n As Integer, p As Integer
p = 1
For i = 2 To 0 Step -1
（4）
p = p + 1
Next i
zh = Str(n)
End Function
2) 补充代码（2001春二（7））
下面程序是把给定的16进制正整数转换为10进制数。
Option Explicit
Private Sub Form_Click()
Dim St As Integer， Dem As Long
St=InputBox("输入一个十六进制数")
Dem=Convert(St)
Print St; ">="; Dem
End Sub
Private Function Convert(S As String)As Long
Dim N As Integer， I As Integer，Substring As String*1
Dim P As long， K As Long，Asc1 As Integer
N= （1）
P=16^N
For I=1 To N
P=P/16
Substring= （2）
Select Case Substring
Case "0" To "9"
K=K+P*Val(Substring)
Case （3）
Asc1=Asc(Substring)-Asc("A")+10
（4）
End Select
Next I
（5）
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