我似乎无法发现的错误，逻辑错误? [英] A bug I can't seem to spot, faulty logic?

问题描述

问题描述: 抬起头来一叠硬币.向上翻转最上面的硬币，然后继续:将最上面的2个硬币向上翻转，作为一个单独的堆叠(尾巴，当翻转时变成头部，然后放回到堆叠的尾部，头部(两个硬币翻转在一起，好像粘在一起)).现在，以同样的方式翻转前3个硬币，然后放回堆栈中(得到:尾巴，尾巴，头部(如果有4个硬币将是尾巴，尾巴，尾巴，头部).从第一个硬币重新开始.继续直到所有头都朝上的堆叠为止.

Problem description: Take a stack of coins all heads up. Upturn the topmost coin and then proceed: take the top 2 coins and upturn as a single stack (tail, head becomes when upturned and placed back on the stack tail, head (the two coins are flipped as if glued together)). Now in the same way flip the top 3 coins and place back on the stack (you get: tail, tail, head (and if there were 4 coins that would be tail, tail, tail, head). When you upturn the whole stack begin again with the first coin. Continue until you return to a stack with all heads up.

(希望如此)

有人能看到为什么这个小程序会失败吗?对于我来说，我首先注意到一个错误的示例是当计数达到18时(带6个硬币的堆叠).

Can anybody see why this small program should fail? The example for me where I first notice an error is when count reaches 18 with a stack of 6 coins.

我在电子表格上放置了一个按钮，并调用了FlippingCoins ...

I placed a button on a spreadsheet and call FlippingCoins...

Sub FlippingCoins()
Call theStackOfCoins
Call theFlipping
End Sub


Sub theStackOfCoins()
Worksheets("Sheet3").Cells(1, 3).Select
Columns("A:b").Select
Selection.ClearContents
Range("a3").Select

Dim StackOfCoins As Integer
    StackOfCoins = Worksheets("Sheet3").Cells(1, 3).Value

Dim row As Integer
    row = 0

For theStack = 1 To StackOfCoins
    Worksheets("Sheet3").Cells(row + theStack, 1).Value = True
Next theStack

End Sub

Sub theFlipping()

Dim middleCoin As Integer
    middleCoin = 0
Dim passes As Integer
    passes = 0
Dim Fst As Integer
    Fst = 0
Dim Lst As Integer
    Lst = 0

Dim stack As Integer
    stack = Worksheets("Sheet3").Cells(1, 3).Value

Dim Flip_x_coins As Integer
    Flip_x_coins = 0

Dim count As Integer
    count = 0

Dim Finished As Boolean
    Finished = False

Reset:
    Flip_x_coins = 1
For Flip_x_coins = 1 To stack
    Worksheets("Sheet3").Cells(1, 4).Value = Flip_x_coins
    count = count + 1
    If Flip_x_coins = 1 Then
        Worksheets("Sheet3").Cells(1, 1).Value = Not (Worksheets("Sheet3").Cells(1, 1).Value)
    Else
        passes = Int(Flip_x_coins) / 2
        Fst = 1
        Lst = Flip_x_coins
        For pass = 1 To passes
            If Worksheets("Sheet3").Cells(Fst, 1).Value = Worksheets("Sheet3").Cells(Lst, 1).Value Then
                    Worksheets("Sheet3").Cells(Fst, 1).Value = Not (Worksheets("Sheet3").Cells(Fst, 1).Value)
                    Worksheets("Sheet3").Cells(Lst, 1).Value = Not (Worksheets("Sheet3").Cells(Lst, 1).Value)
            End If
            Fst = Fst + 1
            Lst = Flip_x_coins - 1
        Next pass
        If Flip_x_coins Mod 2 > 0 Then
            middleCoin = (Flip_x_coins + 1) / 2
            Worksheets("Sheet3").Cells(middleCoin, 1).Value = Not (Worksheets("Sheet3").Cells(middleCoin, 1).Value)
        End If
    End If
    For testComplete = 1 To stack
        If Worksheets("Sheet3").Cells(testComplete, 1).Value = False Then
            Finished = False
            Exit For
        Else
            Finished = True
        End If
    Next testComplete
    Worksheets("Sheet3").Cells(1, 2).Value = count
If Finished = True Then
    Exit For
End If
    MsgBox "Next."
    If Flip_x_coins = stack Then
        GoTo Reset
    End If
Next Flip_x_coins

End Sub

预先感谢

致谢

推荐答案

在For pass = 1 To passes循环中，Lst = Flip_x_coins - 1是错误的.

应为:Lst = Lst - 1

在传递带有6个硬币的第18张时，宏会比较第1行和第6行，然后比较第2行和第5行，然后比较第3行和第5行.显然，最后一次比较应该是在第3行和第4行之间.

On pass 18 with 6 coins, the macro compares rows 1 and 6 followed by rows 2 and 5 followed by rows 3 and 5. Obviously the last comparison should be between rows 3 and 4 instead.

我希望这不是家庭作业，因为宏还有很多其他问题.例如:

I hope this isn't homework because there are lots of other problems with the macro. For example:

宏的开头
• 否Option Explicit.这使您可以使用未声明的三个变量-theStack，pass，testComplete
• 舍入不正确.假定Flip_x_coins是Integer类型，则passes = Int(Flip_x_coins) / 2是无意义的.试试passes = Int(Flip_x_coins / 2)代替
• 使用Goto通常不是一个好主意.它在VBA中用于错误处理，但在这种情况下，您可以轻松地使用Do Until finished ... Loop构造

• no Option Explicit at the start of the macro. This has allowed you to use three variables which you haven't declared - theStack, pass, testComplete
• incorrect rounding. Given that Flip_x_coins is of Integer type, passes = Int(Flip_x_coins) / 2 is nonsense. Try passes = Int(Flip_x_coins / 2) instead
• using Goto is generally a bad idea. It has some use in VBA for error handling but, in this case, you could easily use a Do Until finished ... Loop construct instead

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