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有如下 Visual Basic 程序段:
s = 0
For k = To 5 s = s + k
Next k
该程序段运行后,循环体 s = s + k 被执行 10 次,则循环变量 k 的初值是( )
s = 0
For k = To 5 s = s + k
Next k
该程序段运行后,循环体 s = s + k 被执行 10 次,则循环变量 k 的初值是( )
A.14 | B.-5 | C.1 | D.-4 |
下列能表示"x 大于0 且 x 小于10"的Visual Basic表达式是( )
A.x > 0 Or x < 10 | B.x >= 0 And x < 10 |
C.x >= 0 And x <= 10 | D.x > 0 And x < 10 |
(加试题)某VB程序段如下:
s = ""
For i = 1 To 5
a(i) = 0
Next i
For i = 2 To 5
For j = i To 5
If j Mod i = 0 Then a(j) = 1 - a(j)
Next j
Next i
For i = 1 To 5
If a(i) = 1 Then s = s + Str(i)
Next i
Text1.Text = s
运行该程序段后,Text1中显示的内容为
s = ""
For i = 1 To 5
a(i) = 0
Next i
For i = 2 To 5
For j = i To 5
If j Mod i = 0 Then a(j) = 1 - a(j)
Next j
Next i
For i = 1 To 5
If a(i) = 1 Then s = s + Str(i)
Next i
Text1.Text = s
运行该程序段后,Text1中显示的内容为
A.2 3 5 | B.1 4 | C.2 5 | D.2 3 4 |
(加试题)小明编写了一个统计字符串中数字字符串之和的VB程序(如字符串“ab12.3cd34ef9”,中数字字符串之和为58:12+3+34+9),运行界面如图所示。在文本框Text1中输入字符串s,单击“统计”按钮Command1,在Label3中输出统计结果。

实现上述功能的VB程序代码如下,但划线处代码有错,请改正。
Private Sub Command1_Click()
Dim s As String, ch As String
Dim ch2 As String, sum As Double
Dim n As Integer, i As Integer
s = Text1.Text
n = Len(s)
ch = Mid(s, i, 1)
If ch >= "0" And ch <= "9" Then
j = i
ch2 = Mid(s, j, 1)
Do While ch2 >= "0" And ch2 <= "9"
j = j + 1
ch2 = Mid(s, j, 1)
Loop
sum = sum + Val(Mid(s, i, j – i - 1)) '②_____________
i = j
End If
i = i + 1
Loop
Label3.Caption = Str(sum)
End Sub

实现上述功能的VB程序代码如下,但划线处代码有错,请改正。
Private Sub Command1_Click()
Dim s As String, ch As String
Dim ch2 As String, sum As Double
Dim n As Integer, i As Integer
s = Text1.Text
n = Len(s)
i = 1: sum = 0
Do While i < n '①_____________ch = Mid(s, i, 1)
If ch >= "0" And ch <= "9" Then
j = i
ch2 = Mid(s, j, 1)
Do While ch2 >= "0" And ch2 <= "9"
j = j + 1
ch2 = Mid(s, j, 1)
Loop
sum = sum + Val(Mid(s, i, j – i - 1)) '②_____________
i = j
End If
i = i + 1
Loop
Label3.Caption = Str(sum)
End Sub
(加试题)异或的数学符号为“⊕”,其运算法则相当于不带进位的二进制加法:0⊕0=0,1⊕0=1,0⊕1=1,1⊕1=0(即符号两侧数值相同时,计算结果为0;数值不同时为1)。
如果要对两个十进制数进行异或运算,可以按以下步骤进行:
① 先将要进行异或运算的两个十进制数分别转换为二进制;
② 对两个二进制数按位进行异或运算;例:(101101)2⊕(111)2=(101010)2
③ 再把步骤②中的运算结果转换为十进制,该十进制数即为运算结果。
小明编写了一个VB程序来模拟上述运算过程,程序功能如下:在文本框Text1和Text2中分别输入要参加异或运算的十进制数,单击计算按钮Command1,程序对输入的两个数进行异或运算,并将运算结果显示在文本框Text3中,程序运行界面如图所示。
(2)实现上述功能的VB程序如下。请在划线处填入合适的代码。
Private Sub Command1_Click()
Dim a As Integer, b As Integer, c As Integer
Dim a1 As String, b1 As String
Dim lena1 As Integer, lenb1 As Integer, i As Integer
Dim result As String
a = Val(Text1.Text)
b = Val(Text2.Text)
If a > b Then
c = a: a = b: b = c
End If
result = ""
a1 = DtoB(a): b1 = DtoB(b)
lena1 = Len(a1): lenb1 = Len(b1)
i = 1
Do While i <= lena1
If Mid(a1, lena1 - i + 1, 1) = Mid(b1, lenb1 - i + 1, 1) Then
result = "0" + result
Else
result = "1" + result
End If
i = i + 1
Loop
result =①_____
Text3.Text = BtoD(result)
End Sub
Public Function DtoB(x As Integer) As String
Dim remainder As String
DtoB = ""
Do While x > 0
remainder = CStr(x Mod 2) '如:CStr(3 Mod 2)的值为"1"
DtoB = remainder + DtoB
②________
Loop
End Function
Public Function BtoD(x As String) As Integer
Dim i As Integer
BtoD = 0
For i = 1 To Len(x)
BtoD =③________+ Val(Mid(x, i, 1))
Next i
End Function
如果要对两个十进制数进行异或运算,可以按以下步骤进行:
① 先将要进行异或运算的两个十进制数分别转换为二进制;
② 对两个二进制数按位进行异或运算;例:(101101)2⊕(111)2=(101010)2
③ 再把步骤②中的运算结果转换为十进制,该十进制数即为运算结果。
小明编写了一个VB程序来模拟上述运算过程,程序功能如下:在文本框Text1和Text2中分别输入要参加异或运算的十进制数,单击计算按钮Command1,程序对输入的两个数进行异或运算,并将运算结果显示在文本框Text3中,程序运行界面如图所示。
(2)实现上述功能的VB程序如下。请在划线处填入合适的代码。
Private Sub Command1_Click()
Dim a As Integer, b As Integer, c As Integer
Dim a1 As String, b1 As String
Dim lena1 As Integer, lenb1 As Integer, i As Integer
Dim result As String
a = Val(Text1.Text)
b = Val(Text2.Text)
If a > b Then
c = a: a = b: b = c
End If
result = ""
a1 = DtoB(a): b1 = DtoB(b)
lena1 = Len(a1): lenb1 = Len(b1)
i = 1
Do While i <= lena1
If Mid(a1, lena1 - i + 1, 1) = Mid(b1, lenb1 - i + 1, 1) Then
result = "0" + result
Else
result = "1" + result
End If
i = i + 1
Loop
result =①_____
Text3.Text = BtoD(result)
End Sub
Public Function DtoB(x As Integer) As String
Dim remainder As String
DtoB = ""
Do While x > 0
remainder = CStr(x Mod 2) '如:CStr(3 Mod 2)的值为"1"
DtoB = remainder + DtoB
②________
Loop
End Function
Public Function BtoD(x As String) As Integer
Dim i As Integer
BtoD = 0
For i = 1 To Len(x)
BtoD =③________+ Val(Mid(x, i, 1))
Next i
End Function
求10个[61,100]之间的随机整数的和,其算法的部分流程图如图所示,

图中①②处应分别填入

图中①②处应分别填入
A.i<=10? Int(Rnd*40)+61 |
B.i<=10? Int(Rnd*39)+61 |
C.i<=100? Int(Rnd*40)+61 |
D.i<=100? Int(Rnd*40)+60 |
回文字符串是一个对称的字符串,它从左到右读和从右到左读是完全一样的。如“abcba”和“abccba”都是回文字符串,“abc”不是回文字符串。小王编写了一个验证回文字符串的VB程序,功能如下:在文本框Text1里输入一个字符串,单击命令按钮Command1,在文本框Text2中显示验证结果:是回文字符串显示“yes”,否则显示“no”。程序运行界面如图所示。

(1)在设计程序界面时,要窗体Form1的标题栏上显示“判断回文字符串”,应修改Form1的_________属性。
(2)实现上述功能的VB程序如下,请在划线处填入合适代码。
Private Sub Command1_Click()
Dim st As String
Dim i As Integer, j As Integer
Dim flag As Boolean
①________
j = Len(st)
i = 1
flag = True
Do While flag And i <= j
If Mid(st, i, 1) = Mid(st, j, 1) Then
i = i + 1
②________
Else
flag = False
End If
Loop
If ③______ Then
Text2.Text = "yes"
Else
Text2.Text = "no"
End If
End Sub

(1)在设计程序界面时,要窗体Form1的标题栏上显示“判断回文字符串”,应修改Form1的_________属性。
(2)实现上述功能的VB程序如下,请在划线处填入合适代码。
Private Sub Command1_Click()
Dim st As String
Dim i As Integer, j As Integer
Dim flag As Boolean
①________
j = Len(st)
i = 1
flag = True
Do While flag And i <= j
If Mid(st, i, 1) = Mid(st, j, 1) Then
i = i + 1
②________
Else
flag = False
End If
Loop
If ③______ Then
Text2.Text = "yes"
Else
Text2.Text = "no"
End If
End Sub
某Visual Basic程序如下:
Private Sub Command1_Click()
Dim i As Integer, sum As Integer
sum = 0
For i = 10 To 2 Step -2
sum = sum + i
Next i
Text1.Text = Str(sum)
End Sub
运行程序,单击命令按钮Command1后弹出如图所示的出错信息提示,此时程序正执行的语句是( )

Private Sub Command1_Click()
Dim i As Integer, sum As Integer
sum = 0
For i = 10 To 2 Step -2
sum = sum + i
Next i
Text1.Text = Str(sum)
End Sub
运行程序,单击命令按钮Command1后弹出如图所示的出错信息提示,此时程序正执行的语句是( )

A.Sum = 0 | B.For i = 10 To 2 Step -2 |
C.sum = sum + i | D.Text1.Text = Str(sum) |
编写VB程序,实现如下功能:在文本框Text1、Text2中分别输入一个正整数,单击“计算累加和”按钮(Command1),在标签Label3中显示起始值与结束值之间所有奇数的和。界面如下方左图所示。


(1)在设计应用程序界面时,应使用上方右图所示“控件工具箱”中的___________(填写相应编号)添加“计算累加和”按钮。
(2)为实现上述功能,请在划线处填入合适代码。
Private Sub Command1_Click()
Dim x1 As Integer, x2 As Integer, n As Integer
Dim sum As Long
x1 = Val(Text1.Text)
x2 = Val(Text2.Text)
Sum = 0
If x1 < x2 Then n = 1 Else ①___________
For i = x1 To x2 Step n
If ②___________ Then
Sum = Sum + i
③___________
Next i
Label3.Caption = "从" & x1 & "到" & x2 & "之间所有奇数的累加和=" & Str(Sum)
End Sub