private void btnDiv_Click(object sender, EventArgs e)
        {
            mathJ calc = new mathJ();

            try
            {
                Oper1 = Convert.ToDouble(Input);
            }
            catch (Exception except1)
            {
                Input = "0";
                MessageBox.Show(except1.Message);
            }



            OP = "/";

            //calc.Add(Input);
            // calc.Op = "/";



            Input = string.Empty;
        }
        private void btnEql_Click(object sender, EventArgs e)
        {
            mathJ calc = new mathJ();



            try
            {
                Oper2 = Convert.ToDouble(Input);
            }
            catch (Exception except1)
            {
                Input = "0";
                MessageBox.Show(except1.Message);
            }


            calc.Equals(Oper1, Oper2, OP);



            Input = Convert.ToString(calc.CurrentValue);

            if (OP == "/" && Oper2 == 0)
            {
                Input        = null;
                txtShow.Text = "Error";
                MessageBox.Show("Invalid division by 0 found");
            }

            txtShow.Text = Input;

            WriteData(calc.CurrentValue);
        }
        private void btnNegative_Click(object sender, EventArgs e)
        {
            Input = txtShow.Text;

            if (Input != "0")
            {
                mathJ calc = new mathJ();

                try
                {
                    Oper1 = Convert.ToDouble(Input);
                }
                catch (Exception except1)
                {
                    Input = "0";
                    MessageBox.Show(except1.Message);
                }

                OP = "-";

                calc.Substract(Input);
                //calc.Op = "+";

                Input        = string.Empty;
                txtShow.Text = Input;
            }

            if (Input == "0")
            {
                Input        = "-";
                txtShow.Text = Input;
            }
        }
        public FrmCalculator()
        {
            InitializeComponent();
            txtShow.Text = "0";
            Input        = null;

            mathJ calc = new mathJ();

            calc.Op = Convert.ToString(txtShow.Text);
        }