VB - 改错练习答案

一.选择结构

'题目：在下面的程序段中过程pd可以判断任意三个数能否构成三角形的三边，利用该过程的判定结果， ' 对能构成三角形的计算其面积，构不成的显示\不能构成三角形\'------------------------------------------------ Option Explicit

Private Sub Form_Click()

'**********FOUND**********

Dim x%, y%, z%, s%, b As Boolean, h As Single x = InputBox(\请输入三角形的边长\y = InputBox(\请输入三角形的边长\z = InputBox(\请输入三角形的边长\b = pd(x, y, z) h = (x + y + z) / 2 '**********FOUND********** If Not b Then

s = Sqr(h * (h - x) * (h - y) * (h - z)) Print \三角形面积是\Else

Print \不能构成三角形\End If End Sub

'**********FOUND********** Public Function pd() As Boolean

If x > 0 And y > 0 And z > 0 And x + y > z And x + z > y And y + z > x Then pd = True Else

pd = False End If End Function

(答案1) Dim x% , y% , z% , s! , b As Boolean , h As Single (答案2) If b=true Then

(答案3) Public Function pd(x%, y%, z%) As Boolean

'------------------------------------------------

'题目:请根据下列描述编写购物优惠程序。某商场为了加速促成商品流通，采用购物打折的优惠办法，

每位顾客一次购物（1）在100元以上者，按九五折优惠；

' （2）在200元以上者，按九折优惠；

（3）在300元以上者，按八折优惠； （4）在500元以上者, 按七折优惠。

'------------------------------------------------ Option Explicit

Private Sub Command1_Click() Dim x As Single, y As Single x = Val(Text1.Text) If x < 100 Then

'**********FOUND********** x = y

Else

If x < 200 Then y = 0.95 * x Else

If x < 300 Then y = 0.9 * x Else

If x < 500 Then y = 0.8 * x Else

y = 0.7 * x

'**********FOUND********** Else If End If End If End If

'**********FOUND********** Text2.Text = x End Sub

(答案1) y = x (答案2) End If

(答案3) Text2.Text = y

'------------------------------------------------ '题目：程序功能根据输入的学习成绩,分别显示

优秀 (90分以上), 良好(75分以上),及格(60分以上), 不及格四个等级.

'------------------------------------------------ Option Explicit

Private Sub Form_Click()

Cls

Dim i As Integer

i = InputBox(\请输入学习成绩\Select Case i

'**********FOUND********** Case 0 < i < 100

MsgBox \成绩应该在0--100之间\

'**********FOUND**********

Case 90

Print \优秀\ Case 75 To 89 Print \良好\ Case 60 To 74 Print \及格\

'**********FOUND********** Case

MsgBox \不及格\End Select End Sub

(答案1) Case is>100 ,is<0 (答案2) Case 90 to 100 (答案3) Case else

二.一般

'------------------------------------------------

'题目:程序功能为求解一元二次方程的实根，请修正程序中错误。 '------------------------------------------------ Option Explicit

Private Sub Form_Load()

Dim a!, b!, c!, root1#, root2#, work As Double a = Val(InputBox(\请输入系数a的值\ b = Val(InputBox(\请输入系数b的值\ c = Val(InputBox(\请输入系数c的值\ '**********FOUND********** work = b * 2 - 4 * a * c If work >= 0 And a <> 0 Then '**********FOUND********** root1 = (Sqr(work)) / (2 * a) '**********FOUND********** root2 = (Sqr(work)) / (2 * a)

Print \有二个实根\ Else

Print \无实根!\ End If End Sub

(答案1) work = b ^ 2 - 4 * a * c

(答案2) root1 = (-b + Sqr(work)) / (2 * a) (答案3) root2 = (-b - Sqr(work)) / (2 * a)

'------------------------------------------------ '题目：求s=72+102+132+……832的值。

'------------------------------------------------ Option Explicit

Private Sub Form_Click()

Cls

Dim s As Long Dim i As Integer

'**********FOUND********** s = 1

'**********FOUND********** For i = 72 To 832

s = s + i

'**********FOUND********** loop 30 Print s End Sub

===(答案1)=== ===(答案2)==== ===(答案3)===

s =0 For i = 72 To 832 step 30 Next i

'------------------------------------------------ '题目：该程序的功能是求出100到200之间的全部素数， ' 并且按每行4个、每个数据之间有10个空格的格式输出。 '------------------------------------------------ Option Explicit

Private Sub Form_Click()

Dim k As Integer, i As Integer, j As Integer k = 0

For i = 100 To 200 '**********FOUND********** For j = 1 To i - 1

If i Mod j = 0 Then Exit For Next j If j = i Then

'**********FOUND********** Print i; Tab(10); k = k + 1

'**********FOUND**********

If k Mod 5 = 0 Then Print ; End If Next i End Sub

(答案1) For j = 2 To i - 1 (答案2) Print i; Space(10); (答案3) If k Mod 4 = 0 Then Print

'------------------------------------------------ '题目: 输入一个字符串，将所有的小写字母都转换为大写字母。 '------------------------------------------------ Option Explicit

Private Sub Form_Click()

Dim s1 As String, s2 As String, i As Integer, t As String s1 = InputBox(\输入字符串，#号结束\ i = 1

'**********FOUND********** s1 = Mid(s1, i, 1) Do While t <> \

'**********FOUND**********

If t >= \ s2 = s2 + t i = i + 1

t = Mid(s1, i, 1) Loop

'**********FOUND********** Print \新字符串为：\

End Sub

(答案1) t = Mid(s1, i, 1)

(答案2) If t >= \(答案3) Print \新字符串为:\

三.级数

'------------------------------------------------

'题目：程序功能：求1+2+3……，直到其和超出3000为止，并输入结果。 '------------------------------------------------ Option Explicit

Private Sub Form_Click()

Cls

Dim i As Integer Dim s As Single i = 0

'**********FOUND********** s = 1 Do

'**********FOUND********** i = i + 2 s = s + i

'**********FOUND********** Loop s > 3000

Print \从1 到:\的和是\End Sub (答案1) s =0

(答案2) i = i + 1

(答案3) Loop until s > 3000

'------------------------------------------------ '题目：用自定义函数的方法求sum（x），求当-1≤x≤1时， ' sum（x）=x/2！+x^2/3!+x^3/4!+……+x^n/(n+1)!，

' 当x〉1或x〈-1时，函数值为0。当n〈=0时，输入数据错误。X、N都是由用户输入。 '------------------------------------------------ Option Explicit

Private Sub Command1_Click() Dim s As Single

Dim n As Integer, x As Single, k As Integer n = Val(InputBox(\ x = Val(InputBox(\ If n <= 0 Then

k = MsgBox(\数据输入错误！\数据输入\ Exit Sub End If s = Sum(x, n) Print s End Sub

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