Vb编程题
1.求自然数1～100之间奇数之和。
Private Sub Form_Click()
  Dim s As Long, i As Integer
  s = 0
  For i = 1 To 100 Step 2
    s = s + i
  Next
  Print s
End Sub
2.求自然数1～100之间偶数之和。
Private Sub Form_Click()
  Dim s As Long, i As Integer
  s = 0
  For i = 2 To 100 Step 2
    s = s + i
  Next
  Print s
End Sub
3.编写程序，在窗体上随机输出一个10--99之间的两位整数。
Private Sub Form_Click()
cl
Randomize
Print Int(Rnd() * 90) + 10
End Sub
4.编程计算从200到1000之间的所有4的倍数之和。
Private Sub Form_Click()
cls
Sum = 0
For i = 200 To 1000 Step 4
  Sum = Sum + i
Next
Print "200-1000中4的倍数和是:"; Sum
End Sub
5. 编程计算从300到1000之间的所有7的倍数之和。
Private Sub Form_Click()
Dim i As Integer, sum As Long
sum = 0
For i = 300 To 1000
  If i Mod 7 = 0 Then
    sum = sum + i
  End If
Next
Print "300-1000中7的倍数和是:"; sum
End Sub
6.编写程序在窗体上计算：5/6+4/5+3/4+2/3+1/2
Private Sub Form_Click()
Dim s As Single, i As Integer, t As Single
  s = 0
  For i = 5 To 1 Step -1
    t = i / (i + 1)
    s = s + t
  Next
  Print s
End Sub
7.在窗体的单击事件中编写程序，从键盘上任意输入3个数，输出最大数。
Private Sub Form_Click()
Dim a As Integer, b As Integer, c As Integer
Dim max As Integer
a = Val(InputBox("请输入第一个数"))
b = Val(InputBox("请输入第二个数"))
c = Val(InputBox("简单的vb程序代码请输入第三个数"))
Print a; b; c
max = a
If b > max Then max = b
If c > max Then max = c
Print "三数中最大数是:"; max
End Sub
8.在窗体的单击事件中编写程序，从键盘上任意输入3个数，输出中间数。
Private Sub Form_Click()
  Dim a As Integer, b As Integer, c As Integer, t As Integer
  Dim m As Integer
  a = InputBox("请输入数据")
  b = InputBox("请输入数据")
  c = InputBox("请输入数据")
  Print a; b; c
  If a > b Then
    t = a
    a = b
    b = t
  End If
  If b < c Then
    m = b
  ElseIf a > c Then
      m = c
  Else
    m = a
  End If
  Print "中间数是"; m
End Sub
本题也可以将三个数排序，输出中间值。
9. 在窗体的单击事件中编写程序，从键盘上任意输入3个数，输出最小数。
Private Sub Form_Click()
Dim a As Integer, b As Integer, c As Integer
Dim min As Integer
a = Val(InputBox("请输入第一个数"))
b = Val(InputBox("请输入第二个数"))
c = Val(InputBox("请输入第三个数"))
Print a; b; c
min = a
If b < min Then min = b
If c < min Then min = c
Print "三数中最小数是:"; min
End Sub
10. 在窗体的单击事件中编写程序，从键盘输入3个数，按从小到大的顺序输出到窗体上。
Private Sub Form_Click()
cls
a = Val(InputBox("a="))
b = Val(InputBox("b="))
c = Val(InputBox("c="))
If a > b Then
  t = a: a = b: b = t
End If
If a > c Then
  t = a: a = c: c = t
End If
If b > c Then
  t = b: b = c: c = t
End If
Print "按从小到大排序后的结果:"; a; "、"; b; "、"; c
End Sub
11.编写程序，通过InputBox函数从键盘上输入4个数,计算并在窗体上显示这4个数的和及平均值。
Private Sub Form_Click()
cls
Sum = 0
For i = 1 To 4
  x = Val(InputBox("接收4个数"))
  Sum = Sum + x
Next
Print "和是"; Sum
Print "平均值是"; Sum / 4
End Sub
12.在窗体的单击事件过程中，编写程序计算1！+2！+3！+ … +20!
方法一：
Private Sub Form_Click()
cls
Sum = 0
x = 1
For i = 1 To 20
  x = x * i
  Sum = Sum + x
Next
Print "1!+2!+...+20!="; Sum
End Sub
方法二：
Private Sub Form_Click()
cls
Sum = 0
For i = 1 To 20
  x = 1
  For j = 1 To i
  x = x * j
  Next
  Sum = Sum + x
Next
Print "1!+2!+...+20!="; Sum
End Sub
13.有一个窗体，窗体中有一个文本框，名称为Text1，有一个按钮，试编写按钮的单击事件，实现计算1！+2！+3！+…+10!,将结果显示在文本框Text1中。例题4-21
Private Sub Command1_Click()
Dim sum As Long, i As Integer, x As Long
sum = 0
x = 1
For i = 1 To 10
  x = x * i
  sum = sum + x
Next
Text1.Text = "1!+2!+...+10!=" + Str(sum)
End Sub
14.编写程序计算：s=1+1/2!+1/3!+…+1/n!,说明：在窗体中有一个文本框控件：Text1,用来接收n的值，有一个标签控件：Label1，用来显示S的值，试编写窗体的单击事件，实现计算与显示功能，只要求写出事件的主要代码，事件过程的起始语句和结束语句可略去。例题4-22
Private Sub Command1_Click()
Dim sum As Single, i As Integer, x As Long
Dim n As Integer
n = Text1.Text
sum = 0
x = 1