下面是一段关于计算变量S的算法,下列能正确描述S的算式是( )
①变量S的初值是0,变量T的初值是1,循环变量A的初值为1;
②循环变量A从1循环到100,且步长为2,做第③步中的2个语句;
③ T="-T:" S=S+A*T
④输出变量S的值
①变量S的初值是0,变量T的初值是1,循环变量A的初值为1;
②循环变量A从1循环到100,且步长为2,做第③步中的2个语句;
③ T="-T:" S=S+A*T
④输出变量S的值
A.1+3+5+7…+100 | B.1+3+5+7…+99 |
C.1-3+5-7…-99 | D.-1+3-5+7…+99 |
【加试题】小王模拟超市收银机扫描商品条形码后计算总价的过程制作了一个VB程序。功能如下:在文本框Text1中输入商品条形码,按回车键后会将已经输入的条形码显示在列表框List1中,同时将商品明细显示在列表框List2中。点击按钮“计算商品总价”后,会将所有商品的总价显示在文本框Text2中。程序界面如图所示:

实现上述功能的部分VB程序如下,请在三个划线处填入合适代码。
'定义全局数组变量
Dim a(1 To 10) As Long
Dim b(1 To 10) As String
'自动加载条形码信息以及对应的商品信息
Private Sub Form_Load()
Dim i As Integer
a(1) = 503741
For i =" 2" To 10
a(i) =" a(i" - 1) + 1
Next i
b(1) = "可乐 5.00"
b(2) = "薯片 7.50"
b(3) = "牛奶 5.60"
b(4) = "橙汁 7.50"
b(5) = "面包 4.00"
b(6) = "蜂蜜 28.00"
b(7) = "蛋糕 12.00"
b(8) = "绿箭 3.50"
b(9) = "饼干 6.00"
b(10) = "雪碧 5.00"
End Sub
'输入条形码,查找条形码,并显示条形码及其对应的商品信息
Private Sub Text1_KeyPress(KeyAscii As Integer)
Dim txm As Long:
Dim i As Integer:
Dim j As Integer
txm = Val(Text1.Text)
If KeyAscii =" 13" Then
If txm >=" 503741" And txm <=" 503750" Then
List1.AddItem txm
Text1.Text = ""
i =" 1:" j = 10
Do While i <= j
①
If txm =" a(m)" Then
List2.AddItem b(m)
Exit Do
ElseIf txm > a(m) Then
i =" m" + 1
Else
②
End If
Loop
Else
MsgBox "条形码输入错误,无此商品"
Text1.Text = ""
End If
End If
End Sub
'计算所购商品的总额
Private Sub Command1_Click()
Dim i As Integer, mx As String, jg As String, sum As Single
For i =" 0" To 9
If List2.List(i) <> "" Then
mx = List2.List(i)
sum =" sum" + Mid(mx, 4)
End If
Next i
Text2.Text = ③
End Sub

实现上述功能的部分VB程序如下,请在三个划线处填入合适代码。
'定义全局数组变量
Dim a(1 To 10) As Long
Dim b(1 To 10) As String
'自动加载条形码信息以及对应的商品信息
Private Sub Form_Load()
Dim i As Integer
a(1) = 503741
For i =" 2" To 10
a(i) =" a(i" - 1) + 1
Next i
b(1) = "可乐 5.00"
b(2) = "薯片 7.50"
b(3) = "牛奶 5.60"
b(4) = "橙汁 7.50"
b(5) = "面包 4.00"
b(6) = "蜂蜜 28.00"
b(7) = "蛋糕 12.00"
b(8) = "绿箭 3.50"
b(9) = "饼干 6.00"
b(10) = "雪碧 5.00"
End Sub
'输入条形码,查找条形码,并显示条形码及其对应的商品信息
Private Sub Text1_KeyPress(KeyAscii As Integer)
Dim txm As Long:
Dim i As Integer:
Dim j As Integer
txm = Val(Text1.Text)
If KeyAscii =" 13" Then
If txm >=" 503741" And txm <=" 503750" Then
List1.AddItem txm
Text1.Text = ""
i =" 1:" j = 10
Do While i <= j
①
If txm =" a(m)" Then
List2.AddItem b(m)
Exit Do
ElseIf txm > a(m) Then
i =" m" + 1
Else
②
End If
Loop
Else
MsgBox "条形码输入错误,无此商品"
Text1.Text = ""
End If
End If
End Sub
'计算所购商品的总额
Private Sub Command1_Click()
Dim i As Integer, mx As String, jg As String, sum As Single
For i =" 0" To 9
If List2.List(i) <> "" Then
mx = List2.List(i)
sum =" sum" + Mid(mx, 4)
End If
Next i
Text2.Text = ③
End Sub
下列关于“控件”属性的说法正确的是( )
A.控件的每一个属性都具有同样的默认值; |
B.所有对象都具有同样的属性; |
C.控件的属性只能在设计时设置,不能在运行时修改; |
D.单击窗体中某控件,在属性窗口中的属性列表框中找到要设置的属性,即可设置其属性值; |
VB语句List1.addItem d(i) 的作用是把数组d的数据添加到列表框对象List1中。该语句中的“addItem”是( )
A.属性名 | B.属性值 | C.方法 | D.事件 |
变量a中存储了一个字符,能够正确判断该字符为数字字符“0”-“9”的VB表达式是( )
A.Asc(a)>="0" Or Asc(a)<=9 |
B.“0”<=a<=”9” |
C.a<="”0”" Or a>=”9” |
D.a>="”0”" and a<=”9” |