第3題解題程式

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FOR迴圈版
Private Sub cmd_no3_Click()
'**************************
'*119-940303 Program Start*
'**************************
Open "A:\940303.SM" For Input As #1
Input #1, n
Close #1
For a = 2 To n - 1                    '用2到N-1去除N
    If (n Mod a) = 0 Then             '如果N可以被2到N-1整除,N就不是質數
    S = n & " is not a prime number"  '顯示N不是質數
    Exit For
    End If
    S = n & " is a prime number"      '如果2到N-1都不能整除N，N就是質數
Next

Txt_no3.Text = "第三題結果：" & S

End Sub

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DO WHILE 迴圈版
Private Sub cmd_no3_Click()
'**************************
'*119-940303 Program Start*
'**************************
Open "A:\940303.SM" For Input As #1
Input #1, n
Close #1
a = 2

Do While a < n
If (n Mod a) = 0 Then
S = n & " is not a prime number"
Exit Do
End If
a = a + 1
S = n & " is a prime number"
Loop

Txt_no3.Text = "第三題結果：" & S

End Sub

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DO WHILE後測試版
Private Sub Cmd_no3_Click()
'**************************
'*119-940303 Program Start*
'**************************
Open "A:\940303.SM" For Input As #1
Input #1, n
Close #1
a = 2
Do
If (n Mod a) = 0 Then
S = n & " is not a prime number"
Exit Do
End If
a = a + 1
S = n & " is a prime number"
Loop While a < n

txt_no3.Text = "第三題結果：" & S


End Sub

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