组合计算.frm

Visual Basic课程举例1 有很好的例题

VERSION 5.00
Begin VB.Form Form1 
   Caption         =   "计算组合数"
   ClientHeight    =   2760
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   5505
   LinkTopic       =   "Form1"
   ScaleHeight     =   2760
   ScaleWidth      =   5505
   StartUpPosition =   3  '窗口缺省
   Begin VB.TextBox Text2 
      BeginProperty Font 
         Name            =   "Arial Black"
         Size            =   18
         Charset         =   0
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   495
      Left            =   2400
      TabIndex        =   3
      Top             =   1140
      Width           =   975
   End
   Begin VB.TextBox Text1 
      BeginProperty Font 
         Name            =   "Arial Black"
         Size            =   18
         Charset         =   0
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   495
      Left            =   660
      TabIndex        =   2
      Top             =   1140
      Width           =   915
   End
   Begin VB.CommandButton Command1 
      Caption         =   "计算"
      BeginProperty Font 
         Name            =   "Arial Black"
         Size            =   18
         Charset         =   0
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   855
      Left            =   3900
      TabIndex        =   0
      Top             =   300
      Width           =   1335
   End
   Begin VB.Label Label4 
      Caption         =   "C="
      BeginProperty Font 
         Name            =   "Arial Black"
         Size            =   18
         Charset         =   0
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   495
      Left            =   180
      TabIndex        =   7
      Top             =   1860
      Width           =   675
   End
   Begin VB.Label Label3 
      Caption         =   "K"
      BeginProperty Font 
         Name            =   "Arial Black"
         Size            =   18
         Charset         =   0
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   435
      Left            =   1920
      TabIndex        =   6
      Top             =   1140
      Width           =   375
   End
   Begin VB.Label Label2 
      Caption         =   "R"
      BeginProperty Font 
         Name            =   "Arial Black"
         Size            =   18
         Charset         =   0
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   495
      Left            =   180
      TabIndex        =   5
      Top             =   1140
      Width           =   375
   End
   Begin VB.Label lblC 
      Appearance      =   0  'Flat
      BackColor       =   &H80000005&
      BeginProperty Font 
         Name            =   "Arial Black"
         Size            =   18
         Charset         =   0
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      ForeColor       =   &H80000008&
      Height          =   555
      Left            =   1080
      TabIndex        =   4
      Top             =   1860
      Width           =   2355
   End
   Begin VB.Label Label1 
      Caption         =   "C=R!/(R-K)!K!"
      BeginProperty Font 
         Name            =   "Arial Black"
         Size            =   18
         Charset         =   0
         Weight          =   400
         Underline       =   0   'False
         Italic          =   0   'False
         Strikethrough   =   0   'False
      EndProperty
      Height          =   555
      Left            =   600
      TabIndex        =   1
      Top             =   60
      Width           =   2775
   End
End
Attribute VB_Name = "Form1"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False

Public Function Gama(m As Integer) As Long
    Gama = 1
    For i = 1 To m
        Gama = Gama * i
    Next i
End Function

Private Sub Command1_Click()
    Dim r%, k%, C&
    
    r = Val(Text1)
    k = Text2
    If r > 1 And k > 1 And r > k Then
        C = Gama(r) / (Gama(r - k) * Gama(k))
        lblC = Format(C)
    Else
        MsgBox "数据错误"
    End If
End Sub