Question

如果感兴趣，宏的目标是使用计算机演示中间值定理（比手动演示定理更强大）。因此数学标签。

我有第一个MsgBox的无限循环的VBA宏。为什么这是无限的？我已经尝试重新定位部分代码来解决这个问题，似乎什么也没做。

Option Explicit
Sub Function1()
Dim Polynomial As String
Dim Sign
Dim counter As Integer
Dim Degree
Dim Coefficient

While Cells(counter + 1, 1).Value <> "" And Cells(counter + 1, 2).Value <> "" '+1 because top row occupied by column A, column B titles. If cell is empty stop.
counter = 1
MsgBox "Enter polynomial by terms."
counter = counter + 1
Degree = Cells(counter + 1, 1).Value 'A2
Coefficient = Cells(counter + 1, 2).Value 'B2

If (Coefficient < 0) Then
Sign = " - " ' if coefficient negative
Else
If Coefficient > 0 Then Sign = " + " ' if coefficient positive
End If

Polynomial = Polynomial & " " & Coefficient & "x^" & Degree 'concatenation string, list polynomial.
counter = 1
counter = counter + 1
Wend
MsgBox Polynomial
End Sub

Answer 1

当你遇到（无意的）无限循环时，要检查的第一件事就是循环条件，看看为什么它永远不会使条件失败并退出。在你的情况下，该测试是关于单元格的值，但重要的是计数器变量，因为这是决定哪些单元格（在此期间可能没有改变值）的原因。

如果您手动浏览程序，您会看到您在多个位置将其设置为1，这通常会在循环中重置它。因此，即使你增加它，下一次通过它会回到1并且你从头开始。作为计数器的一般规则，您希望在循环外部（上方）设置一次初始值，然后在循环体的末尾递增它。

Answer 2

您正在不适当的地方修改您的柜台。试试这个：

Option Explicit

Sub Function1()
Dim Polynomial As String
Dim Sign
Dim counter As Integer
Dim Degree
Dim Coefficient

counter = 1
While Cells(counter, 1).Value <> "" And Cells(counter, 2).Value <> ""
    MsgBox "Enter polynomial by terms."
    Degree = Cells(counter, 1).Value 'A2
    Coefficient = Cells(counter, 2).Value 'B2

    If (Coefficient < 0) Then
    Sign = " - " ' if coefficient negative
    Else
    If Coefficient > 0 Then Sign = " + " ' if coefficient positive
    End If

    Polynomial = Polynomial & " " & Coefficient & "x^" & Degree 'concatenation string, list polynomial.
    counter = counter + 1
Wend
MsgBox Polynomial
End Sub

VBA为什么用MsgBox无限循环？

2 个答案: