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二級VB常用算法(七)數組元素插入刪除- -

VB常用算法(七)數組元素插入刪除- -

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Tag插入    刪除    算法                                          

1、算法說明

數組中元素的插入和刪除一般是在已固定序列的數組中插入或刪除一個元素,使得插入或刪除操作后的數組還是有序的。

基本思路:首先要找到插入位置或要刪除的元素。

1)        插入

代碼如下:

Private Sub Command1_Click()

    Dim a(10) As Integer

    Dim i As Integer, k As Integer

    For i = 0 To 9       '生成數組

        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在數組中的位置

        If 14 < a(k) Then Exit For

    Next k

    For i = 9 To k Step -1 '從最后元素開始逐個后移,騰出位置

        a(i + 1) = a(i)

    Next i

    a(k) = 14            '插入數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

刪除

代碼如下:

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、實戰練習

1)        補充代碼(2001秋二(8))

         C盤根目錄下文件Data4.txt的內容是:24681013579。下面程序的功能是將文件后半部分的奇數分別按序插入到前半部分的適當位置,得到的新數列是:1 2 3 4 5 6 7 8 9 10。(實現方法:第一次調整后的數列是:1 2 4 6 8 10 3 5 7 9第二次調整后的數列是: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)        補充代碼(2001春二(8))

         下面程序得功能是將無序數組中相同得數只保留一個,其余得刪除,并輸出經過刪除后的數組元素,刪除相同數是通過將該數組元素后面的元素在數組內依次前移替換前一個元素的值實現的。數組各元素的值從文件data.txt中讀取。

 

                  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

                                    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

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