16.如果兩個質(zhì)數(shù)的差為2,則這兩個質(zhì)數(shù)稱為孿生質(zhì)數(shù)對;編寫VB程序,實現(xiàn)如下功能:單擊“顯示孿生質(zhì)數(shù)對”按鈕Command1,在列表框list1中顯示100以內(nèi)的所有孿生質(zhì)數(shù)對(運行效果如圖所示)。 實現(xiàn)上述功能的VB代碼如下,但加框處代碼有錯,請改正。 Dim a(1To 50)As Integer Private Sub Command1_Click ( ) Dim i As Integer k=0:i=3 Do While i<=100 If Then‘(1) k=k+1 a(k)=i End If i=i+2 Loop For i=2To k If Then‘(2) List1.AddItem Str(a(i-1))+“和“+Str(a(i)) End If Next i End Sub Function prime(x As Integer) As Boolean prime=False For i=2To Int(Sqr(x)) If x Mod i=0Then prime=True Exit For End If Next i End Function。
17.編寫VB程序,實現(xiàn)如下功能:單擊“排序數(shù)組a”按鈕Command1時,對已有數(shù)組a的數(shù)據(jù)進行升序排列,并顯示在文本框Label1中;單擊“顯示數(shù)組b”按鈕Command2時,將升序數(shù)組b的數(shù)據(jù)顯示在文本框Label2中;再單擊“合并a和b”按鈕Command3時,對數(shù)組a和數(shù)組b升序合并到字符串中,將合并后的數(shù)據(jù)在文本框Label3中顯示.(運行效果如第17題圖所示).實現(xiàn)上述功能的VB代碼如下,請?zhí)钊牒线m代碼. Dim a(1To 6)As Integer Dim b(1To 6)As Integer Private Sub Command1_Click ( )'對數(shù)組a中的數(shù)據(jù)進行排序 Dim i As Integer,j As Integer,k as integer a(1)=53:a(2)=18:a(3)=62:a(4)=22:a(5)=6:a(6)=25 s=““ For i=1To 5 k=i For j=i+1To 6 If a(k)>a(j) Then
Next j If i<>k Then t=a(k):a(k)=a(i):a(i)=t End If Next i For i=1 To 6 s=s+Str(a(i)) Next i Label1.Caption=s End Sub Private Sub Command2_Click ( ) b(1)=3:b(2)=8:b(3)=15:b(4)=27:b(5)=38:b(6)=49 '此處部分代碼省略 End Sub Private Sub Command3_Click ( ) '將數(shù)組a和b中的數(shù)據(jù)逐個比較后添加到新的字符串s中,并將s在label3中顯示 i=1:j=1:s=““ Do While i<=6
j<=6'如果兩數(shù)組都還有數(shù)據(jù)未合并 If
Then s=s+Str(a(i)):i=i+1 Else s=s+Str(b(j)):j=j+1 End If Loop Do While i<=6'只有數(shù)組a還有數(shù)據(jù)未合并 s=s+Str(a(i)):i=i+1 Loop Do While j<=6'只有數(shù)組b還有數(shù)據(jù)未合并 s=s+Str(b(j)):j=j+1 Loop Label3.Caption=s End Sub.