---

double[] A = new double[25];

private void button1_Click(object sender, EventArgs e)
{
    listBox1.Items.Clear();
    listBox2.Items.Clear();
    Random rand = new Random();
    for (int i = 0; i < 25; i++)
    {
        A[i] = rand.Next(-5, 6) + rand.NextDouble();
        listBox1.Items.Add("A[" + i + "] = " + A[i].ToString("F2"));
    }
}

private void button2_Click(object sender, EventArgs e)
{
    listBox2.Items.Clear();
    int negativeCount = 0;
    int rangeCount = 0;

    for (int i = 0; i < 25; i++)
    {
        if (A[i] < 0)
            negativeCount++;
        if (A[i] >= 1 && A[i] <= 2)
            rangeCount++;
    }

    listBox2.Items.Add("Количество отрицательных: " + negativeCount);
    listBox2.Items.Add("Количество элементов в [1,2]: " + rangeCount);
}

int[] Z = new int[35];

private void button1_Click(object sender, EventArgs e)
{
    listBox1.Items.Clear();
    listBox2.Items.Clear();
    Random rand = new Random();
    for (int i = 0; i < 35; i++)
    {
        Z[i] = rand.Next(-5, 11);
        listBox1.Items.Add("Z[" + i + "] = " + Z[i]);
    }
}

private void button2_Click(object sender, EventArgs e)
{
    listBox2.Items.Clear();
    int S = 0;
    long P = 1;
    bool foundOdd = false;

    for (int i = 0; i < 35; i++)
    {
        if (Z[i] % 2 == 0 && Z[i] < 3)
            S += Z[i];

        if (Z[i] % 2 != 0 && Z[i] > 1)
        {
            P *= Z[i];
            foundOdd = true;
        }
    }

    if (!foundOdd) P = 0;
    long R = S + P;

    listBox2.Items.Add("S (сумма чётных < 3) = " + S);
    listBox2.Items.Add("P (произведение нечётных > 1) = " + P);
    listBox2.Items.Add("R = S + P = " + R);
}

int[] Q = new int[20];

private void button1_Click(object sender, EventArgs e)
{
    listBox1.Items.Clear();
    listBox2.Items.Clear();
    Random rand = new Random();
    for (int i = 0; i < 20; i++)
    {
        Q[i] = rand.Next(1, 101);
        listBox1.Items.Add("Q[" + i + "] = " + Q[i]);
    }
}

private void button2_Click(object sender, EventArgs e)
{
    listBox2.Items.Clear();
    listBox2.Items.Add("Остаток 1, 2 или 5 при делении на 7:");

    for (int i = 0; i < 20; i++)
    {
        int remainder = Q[i] % 7;
        if (remainder == 1 || remainder == 2 || remainder == 5)
            listBox2.Items.Add("Q[" + i + "] = " + Q[i] +
                               " (остаток: " + remainder + ")");
    }
}

int[] Mas = new int[10];

private void button1_Click(object sender, EventArgs e)
{
    listBox1.Items.Clear();
    listBox2.Items.Clear();
    Random rand = new Random();
    for (int i = 0; i < 10; i++)
    {
        Mas[i] = rand.Next(-20, 20);
        listBox1.Items.Add("Mas[" + i + "] = " + Mas[i]);
    }
}

private void button2_Click(object sender, EventArgs e)
{
    listBox2.Items.Clear();

    int firstNegIndex = -1;
    for (int i = 0; i < 10; i++)
    {
        if (Mas[i] < 0)
        {
            firstNegIndex = i;
            break;
        }
    }

    if (firstNegIndex == -1 || firstNegIndex == 9)
    {
        listBox2.Items.Add("Нет отрицательных или нет элементов после него");
        return;
    }

    long product = 1;
    listBox2.Items.Add("Первый отрицательный: Mas[" + firstNegIndex + "] = "
                       + Mas[firstNegIndex]);

    for (int i = firstNegIndex + 1; i < 10; i++)
    {
        product *= Mas[i];
        listBox2.Items.Add("Mas[" + i + "] = " + Mas[i]);
    }

    listBox2.Items.Add("Произведение = " + product);
}

int[] Mas = new int[14];

private void button1_Click(object sender, EventArgs e)
{
    listBox1.Items.Clear();
    listBox2.Items.Clear();
    Random rand = new Random();
    for (int i = 0; i < 14; i++)
    {
        Mas[i] = rand.Next(-20, 20);
        listBox1.Items.Add("Mas[" + i + "] = " + Mas[i]);
    }
}

private void button2_Click(object sender, EventArgs e)
{
    listBox2.Items.Clear();
    int sum = 0;
    int firstNegIndex = -1;

    for (int i = 0; i < 14; i++)
    {
        if (Mas[i] < 0)
        {
            firstNegIndex = i;
            break;
        }
        sum += Mas[i];
        listBox2.Items.Add("Mas[" + i + "] = " + Mas[i]);
    }

    if (firstNegIndex == -1)
        listBox2.Items.Add("Отрицательных элементов нет");
    else if (firstNegIndex == 0)
        listBox2.Items.Add("Первый элемент отрицательный, сумма = 0");
    else
    {
        listBox2.Items.Add("Первый отрицательный: Mas[" + firstNegIndex + "] = "
                           + Mas[firstNegIndex]);
        listBox2.Items.Add("Сумма до него = " + sum);
    }
}

int[] Mas = new int[12];

private void button1_Click(object sender, EventArgs e)
{
    listBox1.Items.Clear();
    listBox2.Items.Clear();
    Random rand = new Random();
    for (int i = 0; i < 12; i++)
    {
        Mas[i] = rand.Next(-30, 30);
        listBox1.Items.Add("Mas[" + i + "] = " + Mas[i]);
    }
}

private void button2_Click(object sender, EventArgs e)
{
    listBox2.Items.Clear();
    int sum = 0;

    for (int i = 0; i < 12; i++)
    {
        if (Mas[i] % 2 == 0)
        {
            sum += Mas[i];
            listBox2.Items.Add("Mas[" + i + "] = " + Mas[i]);
        }
    }

    listBox2.Items.Add("Сумма чётных элементов = " + sum);
}