Question

求VB大佬看看这哥问题如何解决 谢谢！！

VB调用子程序，求从m个元素中取出n个元素的排列组合（m>n）。
计算公式为：Cmn=m!/(n!*(m-n)!)

Answer 1

Public Function jiecheng(ByVal n As Integer) As Integer
Dim jc As Integer = 1
For i = 1 To n
jc = jc * i
Next
Return jc
End Function

Public Function jiecheng(ByVal n As Integer) As Double
Dim jc As Double
jc = 1
For i = 1 To n
jc = jc * i
Next
jiecheng = jc
End Function

Private Function Factorial1(intN As Integer) As Integer
'采用递归计算阶乘
If intN = 0 Then
Factorial1 = 1
Else
Factorial1 = Factorial1(intN - 1) * intN
End If
End Function
给你几个阶乘的函数，你可以直接调用阶乘的函数去做哦

Answer 2

Option Explicit

Private Sub Command1_Click()

Dim M As Double, N As Double

InputData M, "M"

InputData N, "N"

If M < N Then

Print "Combination(" & M & "," & N; ")=" & 0

Else

Print "Combination(" & M & "," & N; ")=" & Factorial(M) / (Factorial(N) * Factorial(M - N))

End If

End Sub

Public Sub InputData(ByRef t, ByVal Char As String)

t = InputBox(Char + "=", "输入框", 25)

If Int(Val(t)) <> Val(t) Or Val(t) < 0 Then

MsgBox "数据错误！请重新输入：", 16

InputData t, Char

End If

End Sub

Public Function Factorial(ByVal r)

Dim i As Integer

Factorial = 1

For i = 1 To r

Factorial = Factorial * i

Next i

End Function