Question

vb，画正弦曲线

这个是我简单写的函数
Private Sub Command1_Click()
Picture1.Scale (-10, 10)-(10, -10)
Picture1.Line (-10, 0)-(10, 0)
Picture1.Line (0, -10)-(0, 10)
Dim i As Integer
For i = -8 To 8 Step 0.0001
Picture1.PSet (i, 5 * Sin(i))
Next i
End Sub
问题是sin（）中的变量应该是双精度的，系统应该报错啊，可是运行时vb就死那了，怎么回事，

Answer 1

系统为什么不报错
sin(number)中number可为任何一个有效的数值表达式,显然,i 是合法的.
可是运行时vb就死那了
i + 0.001 = i'(i is Integer),死循环,永远到不了8
修改申明
dim i as Double '或者不定义

Answer 2

Dim i As Integer
i+0.01的结果还是i，i值并没有增加，所以成了死循环。

Private Sub Command1_Click()
Picture1.Scale (-10, 10)-(10, -10)
Picture1.Line (-10, 0)-(10, 0)
Picture1.Line (0, -10)-(0, 10)
Dim i
For i = -8 To 8 Step 0.01
Picture1.PSet (i, 5 * Sin(i))
Next i
End Sub

Answer 3

For i = -8000 To 8000 Step 1
Picture1.PSet (i, 5 * Sin(i/10000))
Next i

Answer 4

好难啊 看不懂