---

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 _42killer
{
    public partial class Form1 : Form
    {
        public bool isClick = false;
        public Form1()
        {
            InitializeComponent();
        }

        private void button_symbol_Click(object sender, EventArgs e)
        {
            if (!textBox_result.Text.Contains(","))
            {
                textBox_result.Text = textBox_result.Text + ",";
            }
        }

        private void button_remove_Click(object sender, EventArgs e)
        {
            if (!string.IsNullOrEmpty(textBox_result.Text))
            {
                textBox_result.Text = textBox_result.Text.Remove(textBox_result.Text.Length - 1);
            }
        }

        private void button_0_Click(object sender, EventArgs e)
        {
            textBox_result.Text = textBox_result.Text + "0";
        }

        private void button_1_Click(object sender, EventArgs e)
        {
            textBox_result.Text = textBox_result.Text + "1";
        }

        private void button_2_Click(object sender, EventArgs e)
        {
            textBox_result.Text = textBox_result.Text + "2";
        }

        private void button_3_Click(object sender, EventArgs e)
        {
            textBox_result.Text = textBox_result.Text + "3";
        }

        private void button_4_Click(object sender, EventArgs e)
        {
            textBox_result.Text = textBox_result.Text + "4";
        }

        private void button_5_Click(object sender, EventArgs e)
        {
            textBox_result.Text = textBox_result.Text + "5";
        }

        private void button_6_Click(object sender, EventArgs e)
        {
            textBox_result.Text = textBox_result.Text + "6";
        }

        private void button_7_Click(object sender, EventArgs e)
        {
            textBox_result.Text = textBox_result.Text + "7";
        }

        private void button_8_Click(object sender, EventArgs e)
        {
            textBox_result.Text = textBox_result.Text + "8";
        }

        private void button_9_Click(object sender, EventArgs e)
        {
            textBox_result.Text = textBox_result.Text + "9";
        }

        private void button_reset_Click(object sender, EventArgs e)
        {
            if (!string.IsNullOrEmpty(textBox_result.Text))
            {
                textBox_result.Text = "";
            }
        }

        private void button_getResult_Click(object sender, EventArgs e)
        {
            char op = ' ';

            if (textBox_result.Text.Contains("+")) op = '+';
            else if (textBox_result.Text.Contains("-")) op = '-';
            else if (textBox_result.Text.Contains("*")) op = '*';
            else if (textBox_result.Text.Contains("/")) op = '/';

            if (op != ' ')
            {
                string[] parts = textBox_result.Text.Split(op);

                if (parts.Length == 2 && double.TryParse(parts[0], out double num1) && double.TryParse(parts[1], out double num2))
                {
                    double result = 0;

                    if (op == '+') result = num1 + num2;
                    else if (op == '-') result = num1 - num2;
                    else if (op == '*') result = num1 * num2;
                    else if (op == '/')
                    {
                        if (num2 == 0)
                        {
                            textBox_result.Text = "Ошибка!";
                            isClick = false;
                            return;
                        }
                        result = num1 / num2;
                    }

                    label_old.Text = textBox_result.Text + "=" + result.ToString();
                    textBox_result.Text = result.ToString();
                    isClick = false;
                }
            }
        }

        private void button_fun1_Click(object sender, EventArgs e)
        {
            if (isClick == true)
            {
                string[] parts = textBox_result.Text.Split('+');

                if (parts.Length == 2 && double.TryParse(parts[0], out double num1) && double.TryParse(parts[1], out double num2))
                {
                    double result = num1 + num2;
                    label_old.Text = textBox_result.Text + "=" + result.ToString();
                    textBox_result.Text = result.ToString() + "+";
                    isClick = true;
                }
                else
                {
                    return;
                }
            }
            else
            {
                textBox_result.Text = textBox_result.Text + "+";
                isClick = true;
            }
        }

        private void button_func2_Click(object sender, EventArgs e)
        {
            if (isClick == true)
            {
                string[] parts = textBox_result.Text.Split('-');

                if (parts.Length == 2 && double.TryParse(parts[0], out double num1) && double.TryParse(parts[1], out double num2))
                {
                    double result = num1 - num2;
                    label_old.Text = textBox_result.Text + "=" + result.ToString();
                    textBox_result.Text = result.ToString() + "-";
                    isClick = true;
                }
                else
                {
                    return;
                }
            }
            else
            {
                textBox_result.Text = textBox_result.Text + "-";
                isClick = true;
            }
        }

        private void button_func3_Click(object sender, EventArgs e)
        {
            if (isClick == true)
            {
                string[] parts = textBox_result.Text.Split('*');

                if (parts.Length == 2 && double.TryParse(parts[0], out double num1) && double.TryParse(parts[1], out double num2))
                {
                    double result = num1 * num2;
                    label_old.Text = textBox_result.Text + "=" + result.ToString();
                    textBox_result.Text = result.ToString() + "*";
                    isClick = true;
                }
                else
                {
                    return;
                }
            }
            else
            {
                textBox_result.Text = textBox_result.Text + "*";
                isClick = true;
            }
        }

        private void button_func4_Click(object sender, EventArgs e)
        {
            if (isClick == true)
            {
                string[] parts = textBox_result.Text.Split('/');

                if (parts.Length == 2 && double.TryParse(parts[0], out double num1) && double.TryParse(parts[1], out double num2))
                {
                    if (num2 == 0)
                    {
                        textBox_result.Text = "Ошибка!";
                        isClick = false;
                        return;
                    }

                    double result = num1 / num2;
                    label_old.Text = textBox_result.Text + "=" + result.ToString();
                    textBox_result.Text = result.ToString() + "/";
                    isClick = true;
                }
                else
                {
                    return;
                }
            }
            else
            {
                textBox_result.Text = textBox_result.Text + "/";
                isClick = true;
            }
        }


        private void button_func5_Click(object sender, EventArgs e)
        {
            if (double.TryParse(textBox_result.Text, out double num))
            {
                double result = Math.Pow(num, 2);
                label_old.Text = textBox_result.Text + "²=" + result.ToString();
                textBox_result.Text = result.ToString();
                isClick = false;
            }
        }

        private void button_func6_Click(object sender, EventArgs e)
        {
            if (double.TryParse(textBox_result.Text, out double num))
            {
                if (num < 0)
                {
                    textBox_result.Text = "Ошибка!";
                    isClick = false;
                    return;
                }

                double result = Math.Sqrt(num);

                label_old.Text = "√(" + num.ToString() + ")=" + result.ToString();
                textBox_result.Text = result.ToString();
                isClick = false;
            }
        }
    }
}