Калкулатор на дроби - опростен

/*
 * Created by SharpDevelop.
 * User: Admin
 * Date: 12.1.2022 г.
 * Time: 13:02
 *
 * To change this template use Tools | Options | Coding | Edit Standard Headers.
 */
using System;
using System.Collections.Generic;
using System.Drawing;
using System.Windows.Forms;

namespace drobi
{
    /// <summary>
    /// Description of MainForm.
    /// </summary>
    public partial class MainForm : Form
    {
        public MainForm()
        {
            //
            // The InitializeComponent() call is required for Windows Forms designer support.
            //
            InitializeComponent();

            //
            // TODO: Add constructor code after the InitializeComponent() call.
            //
        }
        void RadioButtonPlusCheckedChanged(object sender, EventArgs e)
        {
            labelSign.Text = "+";
        }
        void RadioButtonMinusCheckedChanged(object sender, EventArgs e)
        {
            labelSign.Text = "-";
        }
        void RadioButtonPoCheckedChanged(object sender, EventArgs e)
        {
            labelSign.Text = "*";
        }
        void RadioButtonDelCheckedChanged(object sender, EventArgs e)
        {
            labelSign.Text = "/";
        }

        void ButtonCalculateClick(object sender, EventArgs e)
        {
            int a = 0;
            int b = 0;
            int c = 0;
            int d = 0;
            int x, y;

            try
            {
                a = int.Parse(textBoxA.Text);
                b = int.Parse(textBoxB.Text);
                c = int.Parse(textBoxC.Text);
                d = int.Parse(textBoxD.Text);
            }
            catch
            {
                MessageBox.Show("Некоректни входни данни");
                return;
            }

            if (labelSign.Text == "?")
            {
                MessageBox.Show("Изберете действие");
                return;
            }

            if (labelSign.Text == "+")
            {
                x = a * d + b * c;
                y = b * d;
                labelX.Text = x.ToString();
                labelY.Text = y.ToString();
            }
            else if (labelSign.Text == "-")
            {
                x = a * d - b * c;
                y = b * d;
                labelX.Text = x.ToString();
                labelY.Text = y.ToString();
            }
            else if (labelSign.Text == "*")
            {
                x = a * c;
                y = b * d;
                labelX.Text = x.ToString();
                labelY.Text = y.ToString();
            }
            else if (labelSign.Text == "/")
            {
                x = a * d;
                y = b * c;
                labelX.Text = x.ToString();
                labelY.Text = y.ToString();
            }

        }
    }
}