数字抽奖源码

A. 求用VB编的一个抽奖系统，有源代码的，最好有解释。从49个人中抽

Dim p1 As Integer, p2 As Integer, p3 As Integer

'产生一等奖号码
p1 = Rnd * 48 + 0.5 + 1

'产生二等奖号码
Do
p2 = Rnd * 48 + 0.5 + 1
Loop Until p2 <> p1

'产生三等奖号码
Do
p3 = Rnd * 48 + 0.5 + 1
Loop Until p3 <> p1 And p3 <> p2

MsgBox "一等奖：" & p1 & vbCrLf & _
"二等奖：" & p2 & vbCrLf & _
"三等奖：" & p3 & vbCrLf, vbInformation