Табулирование. Построение графиков и сплайнов функции

    Public Class Class1
    Public a1, b1, h1
    Public ReadOnly Property a() As Single
        Get
            Return a1
        End Get
    End Property
    Public ReadOnly Property b() As Single
        Get
            Return b1
        End Get
    End Property
    Public ReadOnly Property h() As Single
        Get
            Return h1
        End Get
    End Property
    Public Sub inputF()
        a1 = CSng(InputBox("введите начальное значение функции"))
        b1 = CSng(InputBox("введите конечное значение функции"))
        h1 = CSng(InputBox("введите шаг"))
    End Sub
 
End Class
 
Public Class Form1
    Dim put As Class1 = New Class1
    Public dx, dy, a, b, h As Single
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim x, y, xmax, ymax, xmin, ymin, dx, dy, xm, xn As Single
        Dim n As Integer
        ymax = -1.0E+38 : ymin = 1.0E+38
        xmax = -1.0E+38 : xmin = 1.0E+38
        put.inputF()
        a = put.a
        b = put.b
        h = put.h
        TextBox2.Text = Str(a)
        TextBox3.Text = Str(b)
        TextBox4.Text = Str(h)
        n = (b - a) / h ^ 2
        x = a
        For i As Integer = 1 To n
            x += h
            y = x + 1 / x
            ListBox1.Items.Add(x)
            ListBox2.Items.Add(y)
            ListBox3.Items.Add(i)
            If x < xmin Then
                xmin = x
            End If
            If x > xmax Then
                xmax = x
            End If
            If y < ymin Then
                ymin = y : xm = x
            End If
            If y > ymax Then
                ymax = y : xn = x
            End If
        Next
        dx = Math.Abs(xmax - xmin)
        dy = Math.Abs(ymax - ymin)
        TextBox1.Text = "Наименьшее значение функции " & Str(ymin) & " при x= " & Str(xm) & vbCrLf & vbCrLf
        TextBox1.Text = TextBox1.Text & "Наименьшее значение функции " & Str(ymin) & " при x= " & Str(xn) & vbCrLf
    End Sub
 
 
 
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        End
    End Sub
 
    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        Me.Hide()
        Form2.Show()
    End Sub
End Class
 
Imports System.Math
 
Public Class Form2
    Private Sub form2_paint(ByVal sender As Object, ByVal el As System.Windows.Forms.PaintEventArgs) Handles Me.Paint
        Dim GF As System.Drawing.Graphics
        GF = Label1.CreateGraphics
        Dim GF2 As System.Drawing.Graphics
        GF2 = Label2.CreateGraphics
        Dim PenColor As New System.Drawing.Pen(System.Drawing.Color.Red)
        GF.DrawLine(PenColor, 50, 0, 50, Label1.Height)
        GF.DrawString("x", Label1.Font, Brushes.DarkRed, Label1.Width - 15, Label1.Height - 25)
        GF.DrawLine(PenColor, 0, Label1.Height - 25, Label1.Width, Label1.Height - 25)
        GF.DrawString("y", Label1.Font, Brushes.DarkRed, Label1.Width \ 2 - 100, 1)
    End Sub
    Private Sub Button2_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button2.Click
        Dim a, b, h, n, x, y, xmax, xmin, ymin, ymax, dx, dy As Single
        Dim k As Integer, p As String
        Dim GF As System.Drawing.Graphics
        GF = Label1.CreateGraphics
        Dim GF2 As System.Drawing.Graphics
        GF2 = Label2.CreateGraphics
        Dim PenColor As New System.Drawing.Pen(System.Drawing.Color.Red)
        Dim x1, y1, x2, y2, x3, y3, x4, y4, xa, ya As Single
        a = Form1.a
        b = Form1.b
        h = Form1.h
        n = (b - a) / h
        ymax = -1.0E+38 : ymin = 1.0E+38
        xmax = -1.0E+38 : xmin = 1.0E+38
        x = a
        For i As Integer = 1 To n
            x += h
            If x < xmin Then
                xmin = x
            End If
            If x > xmax Then
                xmax = x
            End If
            If y < ymin Then
                ymin = y
            End If
            If y > ymax Then
                ymax = y
            End If
        Next
        dx = Math.Abs(xmax - xmin)
        dy = Math.Abs(100)
        'MsgBox("dx=" & dx & "   " & "dy=" & dy)
        x = a : k = 1
        For i As Integer = 1 To n
            x += h
            y = x + (1 / x)
            xa = x * Label1.Width \ dx + 50 : ya = Label1.Height - y * Label1.Height \ dy - 50
            GF.FillEllipse(Brushes.Red, xa, ya, 3, 7)
            p = Mid(Str(x), 1, 4)
            If i Mod 25 = 0 Then
                GF.DrawString(p, Label1.Font, Brushes.DarkRed, xa - 30, Label1.Height - 20)
            End If
 
            If i Mod (n \ 5) = 0 And i > 32 Then
                k += 1
                Select Case k
                    Case 1
                        x1 = xa : y1 = ya
                    Case 2
                        x2 = xa : y2 = ya
                    Case 3
                        x3 = xa : y3 = ya
                    Case 4
                        x4 = xa : y4 = ya
                End Select
            End If
        Next
 
        y = ymax + 10 : h = dy / 5
        For s As Single = 2 To Label1.Height Step 16
            y -= h
            p = Mid(Str(y), 1, 5)
            GF.DrawString(p, Label1.Font, Brushes.DarkRed, 5, s)
        Next
 
        Dim points() As Point = {New Point(x1, y1), New Point(x2, y2), New Point(x3, y3), New Point(x4, y4)}
        For t As Single = 0 To 2.5 Step 0.5
            GF2.DrawCurve(Pens.Blue, points, t)
        Next
    End Sub
 
    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Form1.Show()
    End Sub
 
    Private Sub Button3_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button3.Click
        End
    End Sub
End Class