Option Strict On
Option Explicit On
Imports System.Math
Public Class Form1

    Dim x(), new_mass() As Integer

    'Процедура ввода массива
    Sub vvod(ByRef x() As Integer, ByVal index As Integer)
        Select Case index
            Case 0
                'ввод с клавиатуры
                For i = 0 To UBound(x)
                    x(i) = CInt(Val(InputBox("элемент массива X(" + Str(i) + ")=", "Ввод значений элементов массива X()")))
                Next i
            Case 1
                'ввод генератором случ. чисел
                For i = 0 To UBound(x)
                    x(i) = CInt(Rnd(1) * 100 - 50)
                Next i
            Case 2
                'ввод по формуле
                For i = 0 To UBound(x)
                    x(i) = i * 5 - 15
                Next i
        End Select
    End Sub

    'Процедура вывода массива
    Public Sub PrintL(ByRef x() As Integer, ByRef LB As ListBox)
        Dim y As String = " "
        For i = 0 To UBound(x)
            y = y + Str(x(i)) + Space(4)
        Next i
        LB.Items.Add(y)
    End Sub

    'Процедура сортировки эл-тов массива по возрастанию
    Public Sub sort1(ByRef x() As Integer)
        Dim Box As Integer
        For i = 0 To UBound(x) - 1
            For j = i + 1 To UBound(x)
                If x(i) > x(j) Then
                    Box = x(j)
                    x(j) = x(i)
                    x(i) = Box
                End If
            Next j
        Next i
    End Sub

    'Процедура сортировки эл-тов массива по убыванию
    Public Sub sort2(ByRef x() As Integer)
        Dim m As Integer
        Dim xmax As Integer
        For i = 0 To UBound(x) - 1
            xmax = x(i) : m = i
            For j = i + 1 To UBound(x)
                If x(j) > xmax Then
                    xmax = x(j)
                    m = j
                End If
            Next j
            x(m) = x(i)
            x(i) = xmax
        Next i
    End Sub

    'Процедура удаления отрицательных эл-тов массива
    Public Sub mass_udal(ByRef x() As Integer)
        Dim j, i, n As Integer
        n = UBound(x)
        i = 0
        Do While i <= n
            If x(i) < 0 Then
                For j = i To n - 1
                    x(j) = x(j + 1)
                Next j
                n = n - 1
            Else i = i + 1
            End If
        Loop
        ReDim Preserve x(n)
    End Sub

    'Процедура обработки события загрузки формы
    Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        Label1.Text = "Точное" + Space(3) + "москоское" + Space(3) & " время"
        Label2.Text = CStr(DateTime.Now)
    End Sub

    'Процедура обработки события выбора элем. из ComboBox1
    Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
        Dim index, n As Integer
        index = ComboBox1.SelectedIndex
        'индекс выбр-го эл-та ComboBox1
        ListBox1.Items.Clear()
        ListBox2.Items.Clear()
        n = CInt(TextBox1.Text)
        'кол=во эл-тов массива
        ReDim x(n)
        vvod(x, index)
        'ввод массива в зависимости от индекса выбора
        PrintL(x, ListBox1)
        'вывод исходного массива
    End Sub

    'Процедура обработки события выбора элем. из ComboBox2
    Private Sub ComboBox2_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox2.SelectedIndexChanged
        Dim ind As Integer
        ind = ComboBox2.SelectedIndex
        ListBox2.Items.Clear()
        Select Case ind
            Case 0
                sort1(x)
                'вызов проц. сортировки массива по возр.
            Case 1
                sort2(x)
                'вызов проц. сортировки массива по убыв.
            Case 2
                mass_udal(x)
                'вызов проц.удаления отриц. эл-тов
        End Select
        PrintL(x, ListBox2)
        'вызов проц.вывода результ. массива
    End Sub

    Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        End
    End Sub

    Private Sub Button2_Click(sender As Object, e As EventArgs) Handles Button2.Click
        If proverka(x) = False Then
            MsgBox("В массиве нет чисел кратных 3")
        Else
            form_new_mass(x, new_mass)
            PrintL(new_mass, ListBox3)
            TextBox2.Text = Str(pr(new_mass))
        End If
    End Sub

    Public Function proverka(ByVal x() As Integer) As Boolean
        proverka = False
        For i = 0 To UBound(x)
            If x(i) Mod 3 = 0 Then
                proverka = True
                Exit Function
            End If
        Next
    End Function
    Public Sub form_new_mass(ByVal x() As Integer, ByRef nm() As Integer)
        Dim k As Integer = 0
        For i = 0 To UBound(x)
            If x(i) Mod 3 = 0 Then
                ReDim Preserve nm(k)
                nm(k) = x(i)
                k = k + 1
            End If
        Next
    End Sub

    Public Function pr(ByVal nm() As Integer) As Integer
        Dim p As Integer = 1
        For i = 0 To UBound(nm)
            If nm(i) Mod 3 = 0 Then p = p * nm(i)
        Next
        pr = p
    End Function
End Class