Question

Do While x2 <> Abs(x1) - Abs(f1 / f2)     
   f1 = (4 * x1) - (16 / (x1 ^ 2))
   f2 = 4 + (32 / (x1 ^ 3))
   x2 = (x1) - (f1 / f2)
   ' Output to Screen
   Cells(counter, 1) = x1
   Cells(counter, 3) = f1
   Cells(counter, 4) = f2      
   counter = counter + 1
Loop

上述循环变得无限。我怎么摆脱它？那里的错误是什么？

Answer 1

更好的结构可能是让您的循环条件与目标的差异。此外，我放置了一些错误处理，以避免麻烦的条件。

Do While difference > 0.001
   f1 = (4 * x1) - (16 / (x1 ^ 2))
   f2 = 4 + (32 / (x1 ^ 3))
   x2 = (x1) - (f1 / f2)
   ' Output to Screen
   Cells(counter, 1) = x1
   Cells(counter, 3) = f1
   Cells(counter, 4) = f2
   counter = counter + 1

   'Avoid runaway condition
   If counter > 1000 Then
      MsgBox "WARNING!" & Chr(10) & "1000 cycles exceeded"
      Exit Do
   End If
   'Divison by zero
   If f2 = 0 Then
      MsgBox "ERROR!" & Chr(10) & "Divion by zero"
      Exit Do
   End If

   'calculate difference from target
   difference = Abs(x2 - (Abs(x1) - Abs(f1 / f2)))
Loop

你也可以使用圆函数做这样的事情......

Do While round(x2 - (Abs(x1) - Abs(f1 / f2)),3) <> 0

或者这......

Do While round(x2,3) <> round(Abs(x1) - Abs(f1 / f2),3)

哪个最接近原始代码

有人能告诉我为什么下面给出的代码进入无限循环？

1 个答案: