private void button1_Click(object sender, EventArgs e)
        {

            string a = textBox1.Text;
            string b = textBox2.Text;
            string c = textBox3.Text;
            string d = textBox4.Text;

            if (a != "" && b != "" && c != "" && d != "")
            {
                label1.Text = "Nezadány všechny údaje";
            }
            else
            {

                int h = int.Parse(a);
                int j = int.Parse(b);
                int k = int.Parse(c);
                int l = int.Parse(d);

                else if (j == 0 && l == 0)
                {
                    label1.Text = "Nelze dělit nulou";
                }
                else if ((h / j) < (k / l))
                {
                    label1.Text = "<";
                }
                else if ((h / j) > (k / l))
                {
                    label1.Text = ">";
                }
            }

        }