VB课后答案三四章-朱国华主编.doc

第3章1. Private Sub Command1_Click()Dim a As Integera = Text1.TextText2.Text = -aText3.Text = a 2Text4.Text = Sqr(Abs(a)Text5.Text = a 3Text6.Text = Abs(a) (1 / 3)End Sub2. Private Sub Command1_Click() Dim x As Integer, y As Integer x = Text1.Text y = Text2.Text Text1.Text = y Text2.Text = xEnd Sub3. Private Sub Command1_Click()Dim a As Integer, b As Integer, c As Integer Dim x1 As Single, x2 As Single a = Val(Text1.Text) b = Val(Text2.Text) c = Val(Text3.Text) a * x2+b *x+c=0 x1 = (-b + Sqr(b 2 - 4 * a * c) / (2 * a) x2 = (-b - Sqr(b 2 - 4 * a * c) / (2 * a) Text4.Text = x1 Text5.Text = x2 End SubPrivate Sub Command2_Click() EndEnd Sub第4章1. Private Sub Command1_Click() Dim x As Single x = Val(Text1.Text) If x = 0 Then Text2.Text = Sqr(x) Else MsgBox 该数不能开平方 End If End Sub2. Private Sub Command1_Click()Dim a As Integer, b As Booleana = Text1.TextIf a Mod 5 = 0 And a Mod 7 = 0 Then b = True Label1.Caption = 该数能同时被5和7整除 Else b = False Label1.Caption = 该数不能同时被5和7整除 End IfEnd Sub3. Private Sub Command1_Click() Dim x As Integer x = Val(InputBox(请输入一个百分制成绩 ) Select Case x Case Is 90 Print A Case Is = 80 Print B Case Is = 70 Print C Case Is = 60 Print D Case Else Print E End SelectEnd Sub4. Private Sub Command1_Click()Dim n As Integer, t As Long, s As Longs = 0: t = 1For n = 1 To 9 t = t * n If n Mod 2 0 Then s = s + t Next n Print sEnd Sub5. Private Sub Command1_Click() Dim i As Integer, s As Double, n As Integer n = Val(InputBox(请输入一个正整数) s = 0 For i = 1 To n s = s + (-1) (i + 1) / i Next i Print sEnd SubPrivate Sub Command2_Click() Dim i As Integer, s As Long, n As Integer, t As Integer n = Val(InputBox(请输入一个正整数) s = 0 For i = 1 To n t = t + i s = s + t Next i Print sEnd SubPrivate Sub Command3_Click() Dim i As Integer, s As Double, n As Integer ,t as integer n = Val(InputBox(请输入一个正整数) For i = 1 To n t = i 2 s = s + t Next i Print sEnd SubPrivate Sub Command4_Click() Dim i As Integer, s As Double, n As Integer, t As Integer n = Val(InputBox(请输入一个正整数) s = 0 For i = 1 To n t = (-1) (i - 1) * i * (i + 1) s = s + t Next i Print sEnd SubPrivate Sub Command5_Click() Dim i As Integer, s As Double, n As Integer, t As Integer n = Val(InputBox(请输入一个正整数) For i = 1 To n t = t + i s = s + 1 / t Next i Print sEnd Sub6. Private Sub Command1_Click()Dim i As Integer, count As Integer For i = 1 To 1000 If i Mod 2 0 And i Mod 13 = 0 Then count = count + 1 List1.AddItem i End If Text1.Text = count Next iEnd Sub7. Private Sub Command1_Click()Dim i As IntegerFor i = 2000 To 2100 If i Mod 400 = 0 Or (i Mod 4 = 0 And i Mod 100 0) Then List1.AddItem i End If Next iEnd Sub8. Private Sub Command1_Click()Dim a(1 To 20), i As Integer, s1 As Integer, s2 As Integer, count1 As Integer, count2 As IntegerRandomizeFor i = 1 To 20 a(i) = Int(Rnd * 100) + 1 If a(i) Mod 2 = 0 Then count1 = count1 + 1 s1 = s1 + a(i) Else count2 = count2 + 1 s2 = s2 + a(i) End If Print a(i) Next i Print 奇数和为; s1 / count1 Print 偶数和为; s2 / count2End Sub9. Private Sub Command1_Click() Form1.FontSize = 12 Dim i As Integer For i = 1 To 5 Print Tab(5 + i); String(11 - 2 * i, *) Next i End SubPrivate Sub Command2_Click()Dim i As Integer, j As IntegerFor i = 1 To 5 Print Tab(15 - i); For j = 1 To 2 * i - 1 Print Chr(69 - i + j); Next j Next iEnd Sub10. Private Sub Command1_Click() Dim n As Integer, i As Integer Dim flag As Boolean For n = 100 To 999 flag = True For i = 2 To Int(Sqr(n) If n Mod i = 0 Then flag = False Exit For End If Next i If flag Then List1.AddItem n Next nEnd Sub11. Private Sub Command1_Click()Dim x As Integer, y As Integer, z As Integer For x = 0 To 33 For y = 0 To 49 z = 100 - x - y If 3 * x + 2 * y + z / 2 = 100 Then Print x, y, z End If Next y Next xEnd Sub12. Private Sub Command1_Click()Dim a1 As Integer, a2 As Integer, a3 As Integer, a4 As Singlea1 = 1: a2 = 2: a3 = 3Do a4 = (a1 + a2 + a3) / 2 a1 = a2: a2 = a3: a3 = a4 Count1 = Count1 + 1 Loop Until a4 1200 Print Count1 + 3End Sub13. Private Sub Command1_Click()Dim a() As String, m As String, count1 As Integer, count2 As Integer, b As Integerm = InputBox(请输入字符)b = Len(m)ReDim a(1 To b)For i = 1 To b a(i) = Mid(m, i, 1) If Asc(UCase(a(i) = 65 And Asc(UCase(a(i) = 1 And Val(a(i) = 9 Then count2 = count2 + 1 ElseIf a(i) = 0 Then count2 = count2 + 1 End IfNext iPrint 字母个数为：; count1Print 数字个数为: ; count2End Sub14. Private Sub Command1_Click()Dim i As Integer, count As Integer For i = 100 To 999 If (Val(Mid(Str(i), 2, 1) 3 + Val(Mid(Str(i), 3, 1) 3 + Val(Mid(Str(i), 4, 1) 3) = i Then count = count + 1 End If Next i Print countEnd Sub15. Private Sub Command1_Click()Dim x0 As Single, x1 As Single, e As SingleDim f As Single, f1 As Singlex1 = InputBox(请输入迭代初值)e = InputBox(请输入迭代误差)Do x0 = x1 f = x0 + Log(x0) - 2.13 f1 = 1 + 1 / x0 x1 = x0 - f / f1 Loop Until Abs(x0 - x1) e Print x1End Sub16. Private Sub Command1_Click()Dim a As Single, b As Single, n As Integer, h As Single, i As Integer, s As Single, f1 As Single, f2 As Singlea = 1: b = 5n = I