VB程序题

1、KeyPress

2、KeyAscii >=48 AND KeyAscii <=57

3、Text2.Text &Chr(KeyAscii)

以上是在Text2上将每次符合条件轿键的字符都依次连接起来显示。如果是每次要在Text2上只显示一团庆个字符，则将第3空闭或巧改为：

Chr(KeyAscii)

''1、将输入字符串“abcdef”输出为”fedcba”

Private Sub Invert(ByVal xStr As String, yStr As String)

Dim tempStr As String

Dim I As Integer

I = Len(xStr)

Do While I >= 1

tempStr = tempStr + Mid(xStr, I, 1)

I = I - 1

Loop

yStr = tempStr

End Sub

Private Sub Form_Click()

Dim s1 As String, s2 As String

s1 = "abcdef"

Call Invert(s1, s2)

Print s2

End Sub

''2、如果两个质数的差为2，就称这两个质数为质数对,输出100以内的质数对

Public Function IsP(m As Integer) As Boolean

Dim I As Integer

IsP = True

For I = 2 To Int(Sqr(m))

If m Mod I = 0 Then

IsP = False

Exit For

End If

Next I

End Function

Private Sub Form_Click()

Dim I As Integer

p1 = IsP(3)

For I = 5 To 100 Step 2

p2 = IsP(I)

If p1 And p2 Then Print I - 2, I

p1 = p2

Next I

End Sub

'3、求解一元二次方程猜升，要求a，b，c及解x1，x2都以参数传递的方式与主程序交换数据，输入a，b，c和输出带轮x1,x2的 *** 作都放在主程序中

Sub Equa(A!, B!, C!, x1$, x2$)

If Abs(A) <= 0.000001 Then

MsgBox ("不能构成方程"): Exit Sub

Else

Disc = B * B - 4 * A * C

End If

If Abs(Disc) <= 0.000001 Then

Flag = 1

MsgBox ("方程有等实根")

x1 = -B / (2 * A)

x2 = -B /穗行老 (2 * A)

ElseIf Disc >0.000001 Then

Flag = 2: MsgBox ("方程有两不等实根")

x1 = (-B + Sqr(Disc)) / (2 * A)

x2 = (-B - Sqr(Disc)) / (2 * A)

Else

Flag = 3: MsgBox ("方程有两虚实根")

Realp = (-B) / (2 * A)

imagep = Abs(Disc) / (2 * A)

x1 = Realp &"+" &imagep &"I"

x2 = Realp &"-" &imagep &"I"

End If

End Sub

Private Sub Form_Click()

Dim x1$, x2$

A! = InputBox("输入A值")

B! = InputBox("输入B值")

C! = InputBox("输入C值")

Call Equa(A, B, C, x1, x2)

Print x1, x2

End Sub

1.Long（可以存储更大的数）明耐Integer 也行哦激返春

2.While n >世源 0

3.1 To n

4.f = -f : s = S + f / i

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