21.輸入一個三位數的整數,要求將此三位數的各位上的數字重新排列,組成一個盡可能大的三位數.例如:輸入213,重新排列可得到盡可能大的三位數是321. 現要求編寫VB程序(運行界面如圖所示),實現如下功能:在文本框Text1中輸入一個三位數整數,單擊“求解”按鈕Command1,在文本框Text2中顯示重新組合后的最大三位數整數.某同學按此要求編寫的程序如下,其中函數max(x)用于求解最大三位數整數,但加框處代碼有錯,請改正. ①
②
Function max(x As Integer) As Integer Dim a As Integer,b As Integer,c As Integer,t As Integer a=x\100 b='① c=x mod 10 If a<b Then t=a:a=b:b=t If a<c Then t=a:a=c:c=t If b<c Then t=c:c=b:b=t max='② End Function Private Sub Command1_Click Dim n As Integer,y As Integer n=Val(Text1.Text) y=max(n) Text2.Text=Str(y) End Sub.
.(填:冒泡排序/選擇排序) (2)在程序①和②橫線處填入適當的語句或表達式,把程序補充完整. Dim a(1To 10)As Integer Function f(x As Integer)As Boolean '代碼略 End Function Private Sub Command1_Click( ) Dim n As Integer'n用于統計已經產生的隨機整數個數 Dim i As integer,j As Integer Dim x As Integer,k As Integer Randomize'初始化Rnd函數 n=0 List1.Clear'清除列表框中內容 List2.Clear Do While n<10 x=lnt(Rnd*999)+1'產生[1,999]范圍內的隨機整數 If Not f(x) Then n=n+1 a(n)=x List1.AddItem Str(
) End If Loop For i=1To 9'進行排序 For j=10To i+1
If a(j)<a(j-1)Then k=a(j):a(j)=a(j-1):a(j-1)=k End If Next j Next i For i=1To 10 List2.AddItem Str(a(i)) Next i End Sub.