文档介绍：《Visual Basic程序设计》上机试卷
(本试卷考试时间70分钟)
改错题
【要求】
新建工程,输入以下代码,改正程序中的错误;
改错时,可调整个别语句的位置,但不得增加或删除语句;
以Myfrm1和Myprj1为文件名保存窗体和工程。
【题目】
利用公式K×K+K+17生成一组三位整数,首先找出其中的素数,再从中选出所有升序数。所谓升序数是指其百位数小于十位数,十位数小于个位数的数(下图为程序正确执行时的画面)。
含有错误的源程序如下:
Option Explicit
Private Function prime(n As Integer) As Boolean
Dim K As Integer
prime = False
For K = 1 To Sqr(n)
If n Mod K = 0 Then Exit Function
Next K
prime = True
End Function
Private mand1_Click()
Dim K As Integer, P As Integer, T As String
Dim Pn() As Integer
K = 1
Do
P = K * K - K + 17
T = CStr(P)
If Len(T) = 3 And prime(P) Then
ReDim Preserve Pn(K)
Pn(K) = P
P
ElseIf Len(T) > 3 Then
Exit Sub
End If
K = K + 1
Loop
Call increase(Pn)
End Sub
Private Sub increase(Prm() As Integer)
Dim T(3) As String * 1, i As Integer
Dim j As Integer, P As String
For j = 1 To UBound(Prm)
For i = 1 To 3
T(i) = Mid(Str(Prm(j)), i, 1)
Next i
If T(1) < T(2) And T(2) < T(3) Then
P = P & P