2012年计算机考试二级VB考点及习题（4）

例如：1、if 语句：

Private Sub Form_Click()

Dim x As Integer, y As Integer

Dim z As Single

x = 0.2

y = 1

If (x >= 1) Then

z = Log(x)

ElseIf x >= 0 And x < 1 And y >= 0 Then

z = 2 * x - y

Else

z = Exp(x + y)

End If

Print "z=" + Str(z)

End Sub

结果： z=-1

2、Select Case语句

Private Sub Form_Click()

Dim ch As String, i As Integer

ch = "c"

Select Case ch

Case "A", "a"

i = 1

Case "B", "b"

i = 2

Case "C", "c"

i = 3

Case "D", "d"

i = 4

Case Else

i = 5

End Select

Print "运行结果" + Ucase(ch) + Str(i)

End Sub

结果：运行结果C3

② 循环结构

1、For------Next (循环次数的计算)

特例：

例如：有循环:for I=n1 to n2 step n3 下列哪些语句会影响循环次数( )

A. n1=n1+I

B. n3=2*n3

C. n2=n2+n3

D. I=I+n3

2、Do------Loop (While,Until)

例如：运行下面的程序，单击窗体后在窗体上的内容是( );若将程序中的A语句与B语句的位置互换，再次执行程序，单击窗体后在窗体上显示的内容是( )

Private Sub Form_Click()

Dim a As Integer, b As Integer

a = 0: b = 0

Do While a <= 8

a = a + 2 ’A语句

b = b + a * a ’B语句

Loop

Print a, b

End Sub

例如：窗体上显示的结果：

Private Sub Form_Click()

Dim p As Integer, i As Integer, n As Integer

p = 2: n = 20

For i = 1 To n Step p

p = p + 2

n = n - 3

i = i + 1

If p >= 10 Then Exit For

Next i

Print i, p, n

End Sub

一、 InputBox函数

MsgBox函数 (注意参数含义及顺序)

x=InputBox(_____,______,_______)

写出显示下图信息框的MsgBox函数