1.If语句
行:If 条件 then 语句组1 [else 语句组2]
块:if 条件 then
[语句组1]
[else
[语句组2]
]
end if
2.Select case
select case 表达式:
[case 表达式列表1
[语句块1]]
[case 表达式列表2
[语句块2]]
······
[case else
[语句块n]]
End select
Private Sub Form_Click() Dim intx As Integer intx = InputBox("请输入x的值:") Select Case intx Case Is < 0 MsgBox "函数无定义" Case Is < 20 MsgBox 25 * intx - 5 Case 20 To 50 MsgBox 50 Case Is < 100 MsgBox 5 * intx + 19 Case Else MsgBox 100 End Select End Sub
3.for 循环
注意步长与初值和终值的关系
可用exit for 跳出循环
s=0 For i=1 to 100 s=s+I If s>4000 then exit for Next I
4.while 循环
例子:求1+2+···+100
Private Sub Form_Click() i = 0 s = 0 (do) While i <= 100 s = s + i i = i + 1 wend( Loop) Print s End Sub
5.Do 循环(可以用exit do 跳出循环)
1. do while
循环体
Loop
注意:do while 循环与while循环完全相同,即首先判断条件,当条件成立时重复执行循环体。(例子如上)
2.do ···loop while
注意:此循环是先执行一次,再判断条件。当条件成立时,重复执行循环。
Do
循环体
Loop while 条件
例子:
Private Sub Form_Click() Dim i As Integer Dim s As Integer i = 0 s = 0 Do s = s + i i = i + 1 Loop While i <= 100 Print s End Sub
3.Do Until
注意:DO until与do while结构类似,只是前者在条件不满足时成立,后者反之。
例子:
Private Sub Form_Click() Dim i As Integer Dim s As Integer Do Until i > 100 s = s + i i = i + 1 Loop Print s End Sub
4.DO ···loop until
注意:Do ···loop until 结构与Do until 类似,只是前者是先执行一次循环,再判断,在条件不成立时重复执行循环体。
例子:
Private Sub Form_Click() Dim i As Integer Dim s As Integer Do Until i > 100 s = s + i i = i + 1 Loop Print s End Sub
6.for each 循环
注意:for each 循环与for循环类似,但是for each用于数组或对象集合中的每一个元素重复一组语句,在数组中的运用我们并不陌生。
例子:
Private Sub Form_Click() Dim a(100) As Integer For i = 1 To 100 a(i) = i s = s + a(i) Next i Print s End Sub
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