计算机等级考试二级VB常用算法(7)：排序

1、算法说明数组中元素的插入和删除一般是在已固定序列的数组中插入或删除一个元素，使得插入或删除操作后的数组还是有序的。
基本思路：首先要找到插入位置或要删除的元素。
1)        插入

代码如下：
Private Sub Command1_Click()
    Dim a(10) As Integer
    Dim i As Integer, k As Integer
    For i = 0 To 9       '生成数组
        a(i) = i * 3 + 1
    Print a(i);
    Next i
    Print
    Print "插入14"
    For k = 0 To 9       '查找插入14在数组中的位置
        If 14 < a(k) Then Exit For
    Next k
    For i = 9 To k Step -1 '从最后元素开始逐个后移，腾出位置
        a(i + 1) = a(i)
    Next i
    a(k) = 14            '插入数14
    For i = 0 To 10
        Print a(i);
    Next i
    Print
End Sub    
2)        1       4      7      10     13    16     19     22     25    28
 
K

 
删除     代码如下：
Dim a() as integer
….
ReDim a(1 to n)
…
For i=k+1 to n
a(i-1)=a(i)
Next I
Redim preserve a(1 to n-1)    
2、实战练习 1)        补充代码（2001秋二（8））
         C盘根目录下文件Data4.txt的内容是：2，4，6，8，10，1，3，5，7，9。下面程序的功能是将文件后半部分的奇数分别按序插入到前半部分的适当位置，得到的新数列是：1 2 3 4 5 6 7 8 9 10。（实现方法：第一次调整后的数列是：1 2 4 6 8 10 3 5 7 9第二次调整后的数列是：1 2 3 4 6 8 10 5 7 9）。    
                  Option Explict
                  Private Sub Form_Click()
                           Dim A(10) As Integer,i As Integer,J As Integer
                           Open "c:\Data4.txt" For Input As #12
                           Do   （1） 
                                    J=J+1
                                    Input #12,A(J)
                           Loop
                           Call Insert(A)
                           For i=1 To 10
                                    Print A(i);
                           Next i
                           Print
                           Close #12
                  End Sub    
                  Private Sub Insert(A() As Integer)
                           Dim i As Integer,Putp As Integer,J As Integer
                           Dim Getp As Integer,N As Integer,Tem As Integer
                           N=UBound(A)/2
                           Putp=1
                           Getp=N+1
                           For i=1 To N
                                    Tem=A(Getp)
                                    For J=Getp To Putp +1 Step -1
                                               （2） 
                                    Next J
                                    A(Putp)=Tem
                                    Getp=Getp+1
                                    Putp=  （3） 
                           Next i
                  End Sub    
2)        补充代码（2001春二（8））
         下面程序得功能是将无序数组中相同得数只保留一个，其余得删除，并输出经过删除后的数组元素，删除相同数是通过将该数组元素后面的元素在数组内依次前移替换前一个元素的值实现的。数组各元素的值从文件data.txt中读取。    
                  Option Explict
                  Option Base 1
                  Private Sub Form_Click()
                           Dim I As Integer,J As Integer,K As Integer
                           Dim A()As Integer,T As Integer,M As Integer
                           Open "c:\my documents\2000test\data.txt" For Input As #1
                           Do While  （1） 
                                    I=I+1
                                    Redim Preserve A(I)
                                    Input #1,A(I)
                           Loop
                           M=1:T=  （2） 
                           Do While M<T
                                    I=M+1
                                    Do While I<=T
                                             If A(I)=A(M)Then
                                                      For J=1 To   （3） 
                                                               A(J)=A(J+1)
                                                      Next J
                                                      T=T-1
                                             Else
                                                      I=  （4） 
                                             End If
                                    Loop
                                    M=M+1
                           Loop
                           Redim Preserve A(T)
                           For I=1 To T
                                    Print A(I);
                           Next I
                           Print
                  End Sub