《VB程序设计》课堂例题总结

《VB程序设计》课堂例题总结

消息对话框的使用

Private Sub Command1_Click() If Not IsNumeric(Text1) Then

i% = MsgBox(\你输入的不是数字!\警告\ If i = 4 Then Text1.SetFocus Else End Else

MsgBox \你好\欢迎\End If End Sub

求圆的周长与面积

Private Sub Form_Click() Dim r!, s!, c!

Const pi = 3.14159 ?用户声明常量 r = InputBox(\请输入园的半径：\s = pi * r * r c = 2 * pi * r

MsgBox \园的周长为：\ 面积为：\End Sub

计算三角形的面积

Private Sub Command1_Click() Dim a%, b%, c%, s#, area# Dim str1$

a = Val(InputBox(\ b = Val(InputBox(\ c = Val(InputBox(\ s = (a + b + c) / 2

area = Sqr(s * (s - a) * (s - b) * (s - c)) str1 = \ MsgBox str1 Print str1 End Sub

字体的放大与缩小

随机放大1~3整数倍：Text1.FontSize = Text1.FontSize * Int(Rnd()*3+1) 缩小的比例为任意：Text1.FontSize = Text1.FontSize * Rnd()

连接与求和

Private Sub Command1_Click() Text3.Visible = True

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Text3.Text = Text1.Text & Text2.Text '也可以用Text1.Text + Text2.Text Command1.Enabled = False End Sub

Private Sub Command2_Click()

Text3.Text = Val(Text1.Text) + Val(Text2.Text) End Sub

字符串的替换 方法一：（多个函数）

Private Sub Command1_Click()

i = InStr(Text1, Text2) '在Text1中查找出现Text2内容的位置 k = i + Len(Text2) ' 定位右子串的起始位置 Ls = Left(Text1, i - 1) ' 取左子串

Text4 = Ls + Text3 + Mid(Text1, k) ' 左子串连接替换为子串连接右子串实现替换 '也可以将上面两步合并为 Text4 = Left(Text1, i - 1) + Text3 + Mid(Text1, k) End Sub 方法二：（Replace函数） Private Sub Command2_Click()

Text4 = Replace(Text1, Text2, Text3) End Sub

身份证的查找

Private Sub Command1_Click()

Dim a As String, nl%, yue%, ri%, b%, xb$ a = Text1.Text

nl = 2010 - Val(Mid(a, 7, 4))

'nl = Year(Now()) - Val(Mid(a, 7, 4)) yue = Mid(a, 11, 2) ri = Mid(a, 13, 2) b = Val(Mid(a, 17, 1))

If b Mod 2 = 1 Then xb = \ Label3.Caption = nl

Label5.Caption = yue & \月\日\ Label7.Caption = \你是\End Sub

电话号码升位：将原来任意一个带区号的7位电话号码升到8位，在最前面加8。如020-1234567 → 020-81234567 区号及电话号码确定：

Left(s,4) & ”8” & Right(s,7) 区号及电话号码不确定：

Private Sub Command1_Click() Dim a As String

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a = Text1.Text b = InStr(a, \

Label3.Caption = Left(a, b) & \ 'Label3.Caption = Left(a, b) & \End Sub

求一元二次方程的根

Private Sub Command1_Click() Dim a!, b!, c!, x1!, x2!, y!

a = Val(Text1.Text): b = Val(Text2.Text): c = Val(Text3.Text) y = b ^ 2 - 4 * a * c If y < 0 Then

MsgBox (\方程没有实数根\Else

x1 = (-b + Sqr(y)) / （2 *a） x2 = (-b - Sqr(y)) / （2 *a） Label2.Caption = x1 Label3.Caption = x2 End If End Sub

鸡兔同笼问题：鸡兔同笼，有h个头和f只脚，问有鸡兔各几只？ 判断条件：

1.头和脚的数大于零 2.脚数为偶数

3.脚数是头数的2~4倍之间 设：有鸡c只，兔r只 h=c+r f=2c+4r c=(4h-f)/2 r=(f-2h)/2

Private Sub Command1_Click() Dim H As Integer, F As Integer Dim C As Integer, R As Integer H = Val(Text1.Text) F = Val(Text2.Text)

If F > 0 And H > 0 And F Mod 2 = 0 And F >= H * 2 And F <= H * 4 Then R = (F - 2 * H) / 2 C = H - R

Label3.Caption = \ Else

MsgBox \输入错\ End If End Sub

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加密程序：将“明文”的大写字母随机向右移动1～3位，形成“密码”。

Private Sub Command1_Click() Dim m%,s$

Text1 = UCase(Text1) '变成大写字母

m = Int(Rnd * 3) + 1 '随机为生加密移动的位数 Label2.Caption = \向右移动的位数是：\s = Text1

If s >= \Chr(Asc(s) + m) <= \ '移动后不会超过字母\的字母 s = Chr(Asc(s) + m) '正常右移m位 Else

s = Chr(Asc(s) + m - 26) '移动后超过\的，要减去26 End If Label4 = s End Sub

Private Sub Form_Load() Randomize End Sub

加密程序：根据单选按钮的数字，将明文中每个字母改为其后第n个字母。

Private Sub Command1_Click() Dim m%, k% Text2 = \

m = IIf(Option1.Value = True, 1, IIf(Option2.Value = True, 2, 3)) For i = 1 To Len(Text1) s = Mid(Text1, i, 1)

If \ s = Chr(Asc(s) + m) Else

s = Chr(Asc(s) + m - 26) End If

Text2 = Text2 & s Next i End Sub

显示特殊图形

Private Sub Form_Click()

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Print

For i = 1 To 5

Print Tab(i); String(6 - i, \★\▲\ Next i End Sub

登陆程序判断

Private Sub Command1_Click() If Text1.Text = \ MsgBox \祝贺你，成功登录！\ Else

MsgBox \对不起，口令错误，无法登录！\ Text1.Text = \ Text1.SetFocus End If End Sub

判断能否构成三角形，若能则判断是否等边、等腰、直角三角形

Private Sub Command1_Click() Dim a%, b%, c%

a =Val(InputBox(\ a =Val(InputBox(\ a =Val(InputBox(\

If a > 0 And b > 0 And c > 0 And a + b > c And _ b + c > a And a + c > b Then MsgBox \可以构成三角形\

If a = b And b = c Then

s = s & \，是等边三角形\

ElseIf a = b Or a = c Or b = c Then s = s & \，等腰三角形\

ElseIf a ^ 2 + b ^ 2 = c ^ 2 Or a ^ 2 + c ^ 2 = b ^ 2 Or c ^ 2 + b ^ 2 = a ^ 2 Then s = s & \直角三角形\ End If Else

MsgBox \不可以构成三角形\ End If End Sub

输入一个字符,判断该字符是字母字符、数字字符还是其它字符，并作相应的显示。 方法一：

Private Sub Command1_Click() Dim strc As String * 1

strc = InputBox(\请输入一个符号：\

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