四个数分别是1,2,3,4,选三个,有多少种排列方法,并输出排列顺序,用VB程序写

Private Sub Command1_Click()
Dim a(1 To 4) As Integer,s As String,n As Integer
For i = 1 To 4
a(i) = i
Next
n = 0
Text1.Text = ""
For i = 1 To 2
For j = i + 1 To 3
For k = j + 1 To 4
s = a(i) & " " & a(j) & " " & a(k) & vbCrLf
n = n + 1
Text1.Text = Text1.Text & s
Next
Next
Next
Text1.Text = Text1.Text & "共有 " & n & " 种"
End Su