public partial class Form1 : Form
    {
        Double value = 0;
        String operation = "";
        bool operation_pressed = false;
        public Form1()
        {
            InitializeComponent();
        }



        private void button_click(object sender, EventArgs e)
        {
            {
                if ((wynik.Text == "0")|| (operation_pressed))
                {
                    wynik.Clear();
                }
                Button b = (Button)sender;
                wynik.Text = wynik.Text + b.Text;
            }
        }

        private void ce_Click(object sender, EventArgs e)
        {
            wynik.Text = "0";
        }

        private void operator_click(object sender, EventArgs e)
        {
            Button b = (Button)sender;
            operation = b.Text;
            value = Double.Parse(wynik.Text);
            operation_pressed = true;
            label1.Text = value + " " + operation;
        }

        private void oblicz_Click(object sender, EventArgs e)
        {
            operation_pressed = false;
            NewMethod();
        }

        private void NewMethod()
        {
            label1.Text = "";
            switch (operation)
            {
                case "+":
                    wynik.Text = (value + Double.Parse(wynik.Text)).ToString();
                    break;
                case "-":
                    wynik.Text = (value - Double.Parse(wynik.Text)).ToString();
                    break;
                case "x":
                    wynik.Text = (value * Double.Parse(wynik.Text)).ToString();
                    break;
                case "/":
                    wynik.Text = (value / Double.Parse(wynik.Text)).ToString();
                    break;
                default: break;
            }

        }

        private void c_Click(object sender, EventArgs e)
        {
            wynik.Clear();
            value = 0;
        }
    }