Logical Calculator 2

public class LogicCalculator : Form
{
    private TextBox display;
    private Button[] buttons;
    private string operand1 = "";
    private string operand2 = "";
    private string operation = "";
    private bool operationCompleted = false;

    public LogicCalculator()
    {
        display = new TextBox { Top = 10, Left = 10, Width = 200, ReadOnly = true };
        buttons = new Button[8];
        string[] labels = { "0", "1", "AND", "OR", "NOT", "XOR", "IMPLIES", "EQUIVALENT" };

        Size = new Size(250, 200);
        FormBorderStyle = FormBorderStyle.FixedSingle;
        MaximizeBox = false;

        for (int i = 0; i < 8; i++)
        {
            buttons[i] = new Button
            {
                Text = labels[i],
                Top = 50 + (i / 2) * 30,
                Left = 10 + (i % 2) * 60,
                Width = 50
            };
            buttons[i].Click += new EventHandler(Button_Click);
            Controls.Add(buttons[i]);
        }

        Controls.Add(display);
    }

    private void Button_Click(object sender, EventArgs e)
    {
        Button button = (Button)sender;
        string buttonText = button.Text;

        if (operationCompleted && (buttonText == "0" || buttonText == "1"))
        {
            operand1 = "";
            operand2 = "";
            operation = "";
            operationCompleted = false;
            buttons[0].Enabled = true; // Enable button "0"
            buttons[1].Enabled = true; // Enable button "1"
        }

        if (buttonText == "0" || buttonText == "1")
        {
            if (operation == "" && operand1 == "")
            {
                operand1 = buttonText;
                display.Text = operand1;
                buttons[0].Enabled = false; // Disable button "0"
                buttons[1].Enabled = false; // Disable button "1"
            }
            else if (operation != "" && operand2 == "")
            {
                operand2 = buttonText;
                display.Text = operand1 + " " + operation + " " + operand2;
            }
        }
        else if (buttonText == "AND" || buttonText == "OR" || buttonText == "XOR" || buttonText == "IMPLIES" || buttonText == "EQUIVALENT")
        {
            if (operand1 != "" && operation == "")
            {
                operation = buttonText;
                display.Text = operand1 + " " + operation;
                buttons[0].Enabled = true; // Enable button "0"
                buttons[1].Enabled = true; // Enable button "1"
            }
        }
        else if (buttonText == "NOT")
        {
            if (operand1 != "")
            {
                Convert(ref operand1, out bool a);
                operand1 = (!a).ToString();
                display.Text = operand1;
                operationCompleted = true;
                buttons[0].Enabled = true; // Enable button "0"
                buttons[1].Enabled = true; // Enable button "1"
            }
        }

        if (operand1 != "" && operand2 != "" && operation != "")
        {
            Convert(ref operand1, out bool a);
            Convert(ref operand2, out bool b);
            bool result = false;

            switch (operation)
            {
                case "AND":
                    result = a && b;
                    break;
                case "OR":
                    result = a || b;
                    break;
                case "XOR":
                    result = a ^ b;
                    break;
                case "IMPLIES":
                    result = !a || b;
                    break;
                case "EQUIVALENT":
                    result = a == b;
                    break;
            }

            display.Text = operand1 + " " + operation + " " + operand2 + " = " + result.ToString();

            operand1 = result.ToString();
            operand2 = "";
            operation = "";
            operationCompleted = true;
        }
    }

    public static void Convert(ref string str, out bool a)
    {
        a = str.Equals("1");
    }

    [STAThread]
    static void Main()
    {
        Application.Run(new LogicCalculator());
    }
}