编程练习一到四及答案

1、.编程练习一1.按指定方法编程序实现如下分段函数。 lnx x5 y= ex 1x5 x1方法一：用单行If语句实现运行时，从文本框Text1输入x值，单击“计算”按钮Command1按以上公式计算y值，计算结果保留三位小数，显示于标签Label2上。Private Sub Command1_Click()Private Sub Command1_Click()Dim x As Single, y As Singlex = Val(Text1.Text)If x 5 Then y = Log(x) Else If x = 1 Then y = Exp(x) Else y = Sqr(Abs(x

2、 3 = 2 * x + 1)If x 5 Then y = Log(x)If x = 1 And x = 5 Then y = Exp(x)If x 5 Theny = Log(x)ElseIf x = 1 Theny = Exp(x)Elsey = Sqr(Abs(x 3 + 2 * x + 1)End IfText2.Text = Format(y, 0.000)End SubEnd Sub方法三：用多分支选择语句实现运行时，用输入框（InputBox）输入x值，单击“计算”按钮Command1按以上公式计算y值，计算结果保留三位小数，显示于窗体上。Private Sub Command

3、1_Click()Private Sub Command3_Click()Dim x As Single, y As Singlex = Val(InputBox(请输入x的值)Select Case xCase Is 5y = Log(x)Case Is = 1y = Exp(x)Case Elsey = Sqr(Abs(x 3 + 2 * x + 1)End SelectForm1.ScaleHeight = 100Form1.ScaleWidth = 100CurrentX = 35CurrentY = 90Print Format(y, 0.000)End Sub编程练习二1编程序实现

4、：运行时单击窗体，用输入框（InputBox）输入n的值，求的值，计算结果打印在当前窗体上。Private Sub Form_Click()1Private Sub Form_Click()Dim n As Integer, s As Single, i As Integern = Val(InputBox(请输入n的值：)For i = 1 To n s = s + 1 / (2 * i - 1)Next iCurrentX = 200CurrentY = 2200Print s=; Format(s, 0.000)End Sub2编程序实现：运行时单击窗体，用文本框Text1输入x的值，求

5、小于x的最大值，计算结果显示于标签Label3上。Private Sub Form_Click()2Private Sub Command1_Click()Dim x As Double, F As Double, i As Integerx = Val(Text1.Text)F = 1While F x i = i + 1 F = F * (2 * i - 1)WendF = F / (2 * i - 1)Label3.Caption = Str(F)End SubPrivate Sub Command2_Click()Dim x As Double, F As Double, i As I

6、ntegerx = Val(Text1.Text)F = 1: i = -1While F average num1 = num1 + 1 End Select Next i Label2.Caption = 大于平均分的学生人数为 & Str(num1) End SubPrivate Sub Command2_Click()EndEnd Sub2. 编写程序实现：运行时，单击第一个按钮“生成随机数”（Command1），生成100个100，199之间的随机整数，存于一维数组B中显示于文本框Text1中，单击第二个按钮“求最小数”(Command2)，求出这100个随机整数的最小数，并将结果显

7、示在文本框Text2中。2Dim B(1 To 100) As IntegerPrivate Sub Command1_Click() Text1.Text = Randomize For i = 1 To 100 B(i) = Int(Rnd * 100 + 100) Text1.Text = Text1.Text & Str(B(i) & Space(2) Next i End SubPrivate Sub Command2_Click() Dim Min As Integer Min = B(1) 设变量Min的初始值为数组中的第一个元素值 通过循环依次比较，求最小值 For i = 1

8、 To 100 If B(i) Min Then Min = B(i) Next i Text2.Text = Str(Min) 显示最小值End Sub3编程序实现：运行时，单击命令按钮Command1生成100个-10,10之间的随机整数，保存到数组A中，同时显示于带水平滚动条的文本框Text1中，单击命令按钮Command2对这100个数按从大到小的顺序排序，结果显示于带水平滚动条的文本框Text2中。Dim C(1 To 100) As IntegerPrivate Sub Command1_Click() Text1.Text = Randomize For i = 1 To 100

9、 C(i) = Int(Rnd * 21 - 10) Text1.Text = Text1.Text & Str(C(i) & Space(3) Next iEnd SubPrivate Sub Command2_Click() For i = 1 To 99 For j = i + 1 To 100 If C(i) 0 Then Label3.Caption = 所找的数在第 & Str(k) & 个位置 Else Label3.Caption = 没找到 End If Text2.SetFocus Text2.SelStart = 0 Text2.SelLength = Len(Text2

10、.Text)End Sub编程练习四1（1）编写一个计算表达式 值的函数过程，过程名称为F1。（2）在命令按钮Command1的Click事件过程中编写代码，分别从文本框Text1、Text2、Text3输入a、b、c的值，调用以上函数过程求以下表达式的值，用标签Label5显示计算结果。1Function F1(x, y) F1 = Sqr(Abs(x 3 + y 3)End FunctionPrivate Sub Command1_Click() a = Val(Text1.Text) b = Val(Text2.Text) c = Val(Text3.Text) y = (F1(a, b

11、) + F1(a, c) / F1(b, c) Label5.Caption = Format(y, 0.000)End Sub2.（1）编写一函数过程，过程名称为F2，用于计算 1+2+3+n 的值。（2）在窗体的Click事件过程中，用输入框（InputBox）输入a、b、c的值，调用以上函数过程F2计算以下y值，用消息框（MsgBox函数）显示计算结果。2Function F2(n) Sum = 0 For i = 1 To n Sum = Sum + i Next i F2 = SumEnd FunctionPrivate Sub Form_Click() a = Val(InputB

12、ox(请输入a) b = Val(InputBox(请输入b) c = Val(InputBox(请输入c) y = F2(a) * F2(b) * F2(c) MsgBox y= & Str(y)End Sub3（1）编写一个Sub过程，过程名称为S1，用于计算n！。（2） 编写命令按钮Command1的Click事件过程实现：运行时，单击Command1，分别从文本框Text1、Text2输入m和n的值，调用以上Sub过程S1计算以下y值，计算结果显示在文本框Text3中。3Sub S1(n, f) f = 1 For i = 1 To n f = f * i Next iEnd SubP

13、rivate Sub Command1_Click() m = Val(Text1.Text) n = Val(Text2.Text) Call S1(m, f1) Call S1(n, f2) y = (f1 - f2) / (f1 + f2) Text3.Text = Format(y, 0.0000)End Sub4（1）编写一个Sub过程，过程名称为S2，用于求任意一维数组元素的最大值和最小值。（2）在“生成随机数”按钮Command1的Click事件过程中生成100个-50，50区间的随机整数，显示在第一个文本框Text1中。（3）在命令按钮Command2的Click事件过程中调用以上Sub过程求这些随机整数的最大值和最小值，显示在第二个文本框Text2中。4Dim a(1 To 100) As IntegerSub S2(x() As Integer, Max, Min) k1 = LBound(x) k2 = UBound(x) Max = x(k1) Min = x(k1) For i = k1 To k2 If x(i) Max Then Max = x(i) If x(i) Min Then Min = x(i) Next iEnd SubPrivate Sub Command1_Click() Text1.