simpleCalc

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Windows.Forms;

namespace FirstWFAapp
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();
        }

        private void btnChange_Click(object sender, EventArgs e)
        {
            Button button = (Button)sender;

            int a, b;
            double result = 0;
            bool isResult = true;


            try
            {
                a = int.Parse(tbName.Text);
                b = int.Parse(tbSurname.Text);
            }
            catch {
                MessageBox.Show("Please enter numbers!");
                tbName.Text = tbSurname.Text = "";
                return;

            }

            switch (button.Text)
            {
                case "+":
                    result = a + b;
                    break;
                case "-":
                    result = a - b;
                    break;
                case "*":
                    result = a * b;
                    break;
                case "/":
                    if (b != 0)
                        result = (double)a / b;
                    else
                    {
                       lblScreen.Text = "Don't devide by 0!";
                        isResult = false;
                    }
                    break;

                default:
                    break;
            }

            if (isResult)
                lblScreen.Text = $"{a} {button.Text} {b} = {result}";

            //tbName.Text = "";
            //tbSurname.Text = "";
        }
    }
}