lagrange.frm

该系统分为数学公式编译器和数值计算两大块,数学公式编译器的实现比较复杂,计算系统的实现是利用编译器调用数学公式进行的

VERSION 5.00
Begin VB.Form lagrange 
   Caption         =   "拉格朗日"
   ClientHeight    =   3195
   ClientLeft      =   60
   ClientTop       =   345
   ClientWidth     =   4680
   LinkTopic       =   "Form1"
   ScaleHeight     =   3195
   ScaleWidth      =   4680
   StartUpPosition =   3  '窗口缺省
   Begin VB.CommandButton Command3 
      Caption         =   "复原"
      Height          =   375
      Left            =   3120
      TabIndex        =   10
      Top             =   600
      Width           =   1215
   End
   Begin VB.CommandButton Command2 
      Caption         =   "数据录入"
      Height          =   375
      Left            =   3120
      TabIndex        =   9
      Top             =   1200
      Width           =   1215
   End
   Begin VB.TextBox Text4 
      Height          =   495
      Left            =   1320
      TabIndex        =   7
      Text            =   "Text4"
      Top             =   2040
      Width           =   1215
   End
   Begin VB.CommandButton Command1 
      Caption         =   "插值"
      Height          =   375
      Left            =   3120
      TabIndex        =   6
      Top             =   1920
      Width           =   1215
   End
   Begin VB.TextBox Text3 
      Height          =   495
      Left            =   1320
      TabIndex        =   5
      Text            =   "Text3"
      Top             =   1320
      Width           =   1215
   End
   Begin VB.TextBox Text2 
      Height          =   375
      Left            =   1320
      TabIndex        =   2
      Text            =   "Text2"
      Top             =   720
      Width           =   1215
   End
   Begin VB.TextBox Text1 
      Height          =   375
      Left            =   1320
      TabIndex        =   0
      Text            =   "Text1"
      Top             =   120
      Width           =   1215
   End
   Begin VB.Label Label4 
      Caption         =   "out"
      Height          =   375
      Left            =   240
      TabIndex        =   8
      Top             =   2040
      Width           =   495
   End
   Begin VB.Label Label3 
      Caption         =   "y"
      Height          =   495
      Left            =   360
      TabIndex        =   4
      Top             =   1320
      Width           =   375
   End
   Begin VB.Label Label2 
      Caption         =   "x"
      Height          =   255
      Left            =   360
      TabIndex        =   3
      Top             =   720
      Width           =   495
   End
   Begin VB.Label Label1 
      Caption         =   "n"
      Height          =   255
      Left            =   360
      TabIndex        =   1
      Top             =   240
      Width           =   615
   End
End
Attribute VB_Name = "lagrange"
Attribute VB_GlobalNameSpace = False
Attribute VB_Creatable = False
Attribute VB_PredeclaredId = True
Attribute VB_Exposed = False
 Dim n As Integer
 Dim y As Double
 Dim k As Integer
 Dim xi(0 To 15) As Double
 Dim yj(0 To 15) As Double
 'Dim i, j As Integer
 Static i As Integer
 Static j As Integer
 
 

Function sun(xx0, xx1, n) '矩形积分

Dim h, i%

h = (xx1 - xx0) / n

Sum = 0: x = xx0

For i = 1 To n

t = Sin(x)

Sum = Sum + t * h

x = x + h

Next i

End Function



Private Sub Command1_Click()
 

 y = 0
 k = 0
 
Lp:
 t = 1
 For j = 0 To n
 
 t = (x - xi(j)) * t / (xi(k) - xi(j))
 y = y + t * yk

 If k <> n Then
 k = k + 1
 End If
 Next j
 GoTo Lp
 
 
 Text4.Text = CStr(y)
 
 
 
 
 
End Sub

Private Sub Command2_Click()
  Text1.Enabled = False

 

If i < n - 1 Then

 xi(i) = Val(Text2.Text)
 Print "                                               你已经录入了" + CStr(i + 1) + "个数据"
 i = i + 1

MsgBox xi(i)
Else
MsgBox "error"


End If

 'For j = 0 To n
' yj(j) = Val(Text3.Text)
 'Print "你已经录入了" + CStr(j + 1) + "个数据"
 'Next j
 
 
End Sub

Private Sub Command3_Click()
Text1.Enabled = True
Text4.Enabled = True

End Sub

Private Sub Form_Load()
Text1.Text = " "
Text2.Text = " "
Text3.Text = " "
Text4.Text = " "
 i = j = 0
 n = Val(Text1.Text)

  
 Text4.Enabled = False

End Sub