Добавьте файлы проекта.

App.config

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+<?xml version="1.0" encoding="utf-8" ?>
+<configuration>
+    <startup> 
+        <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.7.2" />
+    </startup>
+</configuration>

Form1.Designer.cs

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+namespace Zharushkin_calculator2
+{
+    partial class Form1
+    {
+        /// <summary>
+        /// Обязательная переменная конструктора.
+        /// </summary>
+        private System.ComponentModel.IContainer components = null;
+
+        /// <summary>
+        /// Освободить все используемые ресурсы.
+        /// </summary>
+        /// <param name="disposing">истинно, если управляемый ресурс должен быть удален; иначе ложно.</param>
+        protected override void Dispose(bool disposing)
+        {
+            if (disposing && (components != null))
+            {
+                components.Dispose();
+            }
+            base.Dispose(disposing);
+        }
+
+        #region Код, автоматически созданный конструктором форм Windows
+
+        /// <summary>
+        /// Требуемый метод для поддержки конструктора — не изменяйте 
+        /// содержимое этого метода с помощью редактора кода.
+        /// </summary>
+        private void InitializeComponent()
+        {
+            this.textBox1 = new System.Windows.Forms.TextBox();
+            this.button1 = new System.Windows.Forms.Button();
+            this.label1 = new System.Windows.Forms.Label();
+            this.button2 = new System.Windows.Forms.Button();
+            this.button3 = new System.Windows.Forms.Button();
+            this.button4 = new System.Windows.Forms.Button();
+            this.button5 = new System.Windows.Forms.Button();
+            this.button6 = new System.Windows.Forms.Button();
+            this.button7 = new System.Windows.Forms.Button();
+            this.button8 = new System.Windows.Forms.Button();
+            this.button9 = new System.Windows.Forms.Button();
+            this.button10 = new System.Windows.Forms.Button();
+            this.button11 = new System.Windows.Forms.Button();
+            this.button12 = new System.Windows.Forms.Button();
+            this.button13 = new System.Windows.Forms.Button();
+            this.button14 = new System.Windows.Forms.Button();
+            this.button15 = new System.Windows.Forms.Button();
+            this.button16 = new System.Windows.Forms.Button();
+            this.button17 = new System.Windows.Forms.Button();
+            this.button18 = new System.Windows.Forms.Button();
+            this.button19 = new System.Windows.Forms.Button();
+            this.SuspendLayout();
+            // 
+            // textBox1
+            // 
+            this.textBox1.Location = new System.Drawing.Point(12, 30);
+            this.textBox1.Multiline = true;
+            this.textBox1.Name = "textBox1";
+            this.textBox1.Size = new System.Drawing.Size(281, 48);
+            this.textBox1.TabIndex = 0;
+            this.textBox1.TextChanged += new System.EventHandler(this.textBox1_TextChanged);
+            // 
+            // button1
+            // 
+            this.button1.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.button1.Location = new System.Drawing.Point(12, 114);
+            this.button1.Name = "button1";
+            this.button1.Size = new System.Drawing.Size(54, 39);
+            this.button1.TabIndex = 1;
+            this.button1.Text = "C";
+            this.button1.UseVisualStyleBackColor = true;
+            this.button1.Click += new System.EventHandler(this.button1_Click);
+            // 
+            // label1
+            // 
+            this.label1.AutoSize = true;
+            this.label1.BackColor = System.Drawing.Color.Yellow;
+            this.label1.Font = new System.Drawing.Font("Microsoft Sans Serif", 14.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.label1.Location = new System.Drawing.Point(22, 42);
+            this.label1.Name = "label1";
+            this.label1.Size = new System.Drawing.Size(0, 24);
+            this.label1.TabIndex = 3;
+            this.label1.Click += new System.EventHandler(this.label1_Click);
+            // 
+            // button2
+            // 
+            this.button2.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.button2.Location = new System.Drawing.Point(88, 114);
+            this.button2.Name = "button2";
+            this.button2.Size = new System.Drawing.Size(54, 39);
+            this.button2.TabIndex = 4;
+            this.button2.Text = "<-";
+            this.button2.UseVisualStyleBackColor = true;
+            this.button2.Click += new System.EventHandler(this.button2_Click);
+            // 
+            // button3
+            // 
+            this.button3.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.button3.Location = new System.Drawing.Point(167, 114);
+            this.button3.Name = "button3";
+            this.button3.Size = new System.Drawing.Size(54, 39);
+            this.button3.TabIndex = 5;
+            this.button3.Text = "+/-";
+            this.button3.UseVisualStyleBackColor = true;
+            this.button3.Click += new System.EventHandler(this.button3_Click);
+            // 
+            // button4
+            // 
+            this.button4.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.button4.Location = new System.Drawing.Point(239, 114);
+            this.button4.Name = "button4";
+            this.button4.Size = new System.Drawing.Size(54, 39);
+            this.button4.TabIndex = 6;
+            this.button4.Text = "+";
+            this.button4.UseVisualStyleBackColor = true;
+            this.button4.Click += new System.EventHandler(this.button4_Click);
+            // 
+            // button5
+            // 
+            this.button5.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.button5.Location = new System.Drawing.Point(239, 173);
+            this.button5.Name = "button5";
+            this.button5.Size = new System.Drawing.Size(56, 39);
+            this.button5.TabIndex = 7;
+            this.button5.Text = "-";
+            this.button5.UseVisualStyleBackColor = true;
+            this.button5.Click += new System.EventHandler(this.button5_Click);
+            // 
+            // button6
+            // 
+            this.button6.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.button6.Location = new System.Drawing.Point(239, 234);
+            this.button6.Name = "button6";
+            this.button6.Size = new System.Drawing.Size(56, 39);
+            this.button6.TabIndex = 8;
+            this.button6.Text = "*";
+            this.button6.UseVisualStyleBackColor = true;
+            this.button6.Click += new System.EventHandler(this.button6_Click);
+            // 
+            // button7
+            // 
+            this.button7.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.button7.Location = new System.Drawing.Point(239, 299);
+            this.button7.Name = "button7";
+            this.button7.Size = new System.Drawing.Size(56, 39);
+            this.button7.TabIndex = 9;
+            this.button7.Text = "/";
+            this.button7.UseVisualStyleBackColor = true;
+            this.button7.Click += new System.EventHandler(this.button7_Click);
+            // 
+            // button8
+            // 
+            this.button8.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.button8.Location = new System.Drawing.Point(167, 354);
+            this.button8.Name = "button8";
+            this.button8.Size = new System.Drawing.Size(128, 39);
+            this.button8.TabIndex = 10;
+            this.button8.Text = "=";
+            this.button8.UseVisualStyleBackColor = true;
+            this.button8.Click += new System.EventHandler(this.button8_Click);
+            // 
+            // button9
+            // 
+            this.button9.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.button9.Location = new System.Drawing.Point(86, 354);
+            this.button9.Name = "button9";
+            this.button9.Size = new System.Drawing.Size(56, 39);
+            this.button9.TabIndex = 11;
+            this.button9.Text = ".";
+            this.button9.UseVisualStyleBackColor = true;
+            // 
+            // button10
+            // 
+            this.button10.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.button10.Location = new System.Drawing.Point(12, 354);
+            this.button10.Name = "button10";
+            this.button10.Size = new System.Drawing.Size(56, 39);
+            this.button10.TabIndex = 12;
+            this.button10.Text = "0";
+            this.button10.UseVisualStyleBackColor = true;
+            this.button10.Click += new System.EventHandler(this.button10_Click);
+            // 
+            // button11
+            // 
+            this.button11.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.button11.Location = new System.Drawing.Point(12, 299);
+            this.button11.Name = "button11";
+            this.button11.Size = new System.Drawing.Size(56, 39);
+            this.button11.TabIndex = 13;
+            this.button11.Text = "1";
+            this.button11.UseVisualStyleBackColor = true;
+            this.button11.Click += new System.EventHandler(this.button11_Click);
+            // 
+            // button12
+            // 
+            this.button12.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.button12.Location = new System.Drawing.Point(88, 299);
+            this.button12.Name = "button12";
+            this.button12.Size = new System.Drawing.Size(56, 39);
+            this.button12.TabIndex = 14;
+            this.button12.Text = "2";
+            this.button12.UseVisualStyleBackColor = true;
+            this.button12.Click += new System.EventHandler(this.button12_Click);
+            // 
+            // button13
+            // 
+            this.button13.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.button13.Location = new System.Drawing.Point(165, 299);
+            this.button13.Name = "button13";
+            this.button13.Size = new System.Drawing.Size(56, 39);
+            this.button13.TabIndex = 15;
+            this.button13.Text = "3";
+            this.button13.UseVisualStyleBackColor = true;
+            this.button13.Click += new System.EventHandler(this.button13_Click);
+            // 
+            // button14
+            // 
+            this.button14.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.button14.Location = new System.Drawing.Point(165, 234);
+            this.button14.Name = "button14";
+            this.button14.Size = new System.Drawing.Size(56, 39);
+            this.button14.TabIndex = 18;
+            this.button14.Text = "6";
+            this.button14.UseVisualStyleBackColor = true;
+            this.button14.Click += new System.EventHandler(this.button14_Click);
+            // 
+            // button15
+            // 
+            this.button15.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.button15.Location = new System.Drawing.Point(88, 234);
+            this.button15.Name = "button15";
+            this.button15.Size = new System.Drawing.Size(56, 39);
+            this.button15.TabIndex = 17;
+            this.button15.Text = "5";
+            this.button15.UseVisualStyleBackColor = true;
+            this.button15.Click += new System.EventHandler(this.button15_Click);
+            // 
+            // button16
+            // 
+            this.button16.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.button16.Location = new System.Drawing.Point(12, 234);
+            this.button16.Name = "button16";
+            this.button16.Size = new System.Drawing.Size(56, 39);
+            this.button16.TabIndex = 16;
+            this.button16.Text = "4";
+            this.button16.UseVisualStyleBackColor = true;
+            this.button16.Click += new System.EventHandler(this.button16_Click);
+            // 
+            // button17
+            // 
+            this.button17.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.button17.Location = new System.Drawing.Point(163, 173);
+            this.button17.Name = "button17";
+            this.button17.Size = new System.Drawing.Size(56, 39);
+            this.button17.TabIndex = 21;
+            this.button17.Text = "9";
+            this.button17.UseVisualStyleBackColor = true;
+            this.button17.Click += new System.EventHandler(this.button17_Click);
+            // 
+            // button18
+            // 
+            this.button18.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.button18.Location = new System.Drawing.Point(86, 173);
+            this.button18.Name = "button18";
+            this.button18.Size = new System.Drawing.Size(56, 39);
+            this.button18.TabIndex = 20;
+            this.button18.Text = "8";
+            this.button18.UseVisualStyleBackColor = true;
+            this.button18.Click += new System.EventHandler(this.button18_Click);
+            // 
+            // button19
+            // 
+            this.button19.Font = new System.Drawing.Font("Microsoft Sans Serif", 8.25F, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Point, ((byte)(204)));
+            this.button19.Location = new System.Drawing.Point(10, 173);
+            this.button19.Name = "button19";
+            this.button19.Size = new System.Drawing.Size(56, 39);
+            this.button19.TabIndex = 19;
+            this.button19.Text = "7";
+            this.button19.UseVisualStyleBackColor = true;
+            this.button19.Click += new System.EventHandler(this.button19_Click);
+            // 
+            // Form1
+            // 
+            this.AutoScaleDimensions = new System.Drawing.SizeF(6F, 13F);
+            this.AutoScaleMode = System.Windows.Forms.AutoScaleMode.Font;
+            this.BackColor = System.Drawing.Color.CornflowerBlue;
+            this.ClientSize = new System.Drawing.Size(305, 450);
+            this.Controls.Add(this.button17);
+            this.Controls.Add(this.button18);
+            this.Controls.Add(this.button19);
+            this.Controls.Add(this.button14);
+            this.Controls.Add(this.button15);
+            this.Controls.Add(this.button16);
+            this.Controls.Add(this.button13);
+            this.Controls.Add(this.button12);
+            this.Controls.Add(this.button11);
+            this.Controls.Add(this.button10);
+            this.Controls.Add(this.button9);
+            this.Controls.Add(this.button8);
+            this.Controls.Add(this.button7);
+            this.Controls.Add(this.button6);
+            this.Controls.Add(this.button5);
+            this.Controls.Add(this.button4);
+            this.Controls.Add(this.button3);
+            this.Controls.Add(this.button2);
+            this.Controls.Add(this.label1);
+            this.Controls.Add(this.button1);
+            this.Controls.Add(this.textBox1);
+            this.Name = "Form1";
+            this.Text = "Калькулятор";
+            this.ResumeLayout(false);
+            this.PerformLayout();
+
+        }
+
+        #endregion
+
+        private System.Windows.Forms.TextBox textBox1;
+        private System.Windows.Forms.Button button1;
+        private System.Windows.Forms.Label label1;
+        private System.Windows.Forms.Button button2;
+        private System.Windows.Forms.Button button3;
+        private System.Windows.Forms.Button button4;
+        private System.Windows.Forms.Button button5;
+        private System.Windows.Forms.Button button6;
+        private System.Windows.Forms.Button button7;
+        private System.Windows.Forms.Button button8;
+        private System.Windows.Forms.Button button9;
+        private System.Windows.Forms.Button button10;
+        private System.Windows.Forms.Button button11;
+        private System.Windows.Forms.Button button12;
+        private System.Windows.Forms.Button button13;
+        private System.Windows.Forms.Button button14;
+        private System.Windows.Forms.Button button15;
+        private System.Windows.Forms.Button button16;
+        private System.Windows.Forms.Button button17;
+        private System.Windows.Forms.Button button18;
+        private System.Windows.Forms.Button button19;
+    }
+}
+

Form1.cs

@@ -0,0 +1,198 @@
+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 Zharushkin_calculator2
+{
+    public partial class Form1 : Form
+    {
+        public Form1()
+        {
+            InitializeComponent();
+        }
+
+        float a, b;
+        int oper;
+        bool znak = true;
+
+        private void calculate()
+        {
+            switch (oper)
+            {
+                case 1:
+                    b = a + float.Parse(textBox1.Text);
+                    textBox1.Text = b.ToString();
+                    break;
+                case 2:
+                    b = a - float.Parse(textBox1.Text);
+                    textBox1.Text = b.ToString();
+                    break;
+                case 3:
+                    b = a * float.Parse(textBox1.Text);
+                    textBox1.Text = b.ToString();
+                    break;
+                case 4:
+
+                    if (float.Parse(textBox1.Text) == 0)
+                    { textBox1.Text = "Делить на 0 нельзя!"; }
+                    else
+                    {
+                        b = a / float.Parse(textBox1.Text);
+                        textBox1.Text = b.ToString();
+                    }
+                    break;
+                default:
+                    break;
+            }
+
+        }
+
+        private void listBox1_SelectedIndexChanged(object sender, EventArgs e)
+        {
+
+        }
+
+        private void button5_Click(object sender, EventArgs e)
+        {
+            a = float.Parse(textBox1.Text);
+            textBox1.Clear();
+            oper = 2;
+            label1.Text = a.ToString() + "-";
+            znak = true;
+        }
+
+        private void button6_Click(object sender, EventArgs e)
+        {
+            a = float.Parse(textBox1.Text);
+            textBox1.Clear();
+            oper = 3;
+            label1.Text = a.ToString() + "*";
+            znak = true;
+        }
+
+        private void button7_Click(object sender, EventArgs e)
+        {
+            a = float.Parse(textBox1.Text);
+            textBox1.Clear();
+            oper = 4;
+            label1.Text = a.ToString() + "/";
+            znak = true;
+        }
+
+        private void button3_Click(object sender, EventArgs e)
+        {
+            if (znak == true)
+            {
+                textBox1.Text = "-" + textBox1.Text;
+                znak = false;
+            }
+            else if (znak == false)
+            {
+                textBox1.Text = textBox1.Text.Replace("-", "");
+                znak = true;
+            }
+        }
+
+        private void button10_Click(object sender, EventArgs e)
+        {
+            textBox1.Text = textBox1.Text + 0;
+        }
+
+        private void button11_Click(object sender, EventArgs e)
+        {
+            textBox1.Text = textBox1.Text + 1;
+        }
+
+        private void button12_Click(object sender, EventArgs e)
+        {
+            textBox1.Text = textBox1.Text + 2;
+        }
+
+        private void button13_Click(object sender, EventArgs e)
+        {
+            textBox1.Text = textBox1.Text + 3;
+        }
+
+        private void button16_Click(object sender, EventArgs e)
+        {
+            textBox1.Text = textBox1.Text + 4;
+        }
+
+        private void button15_Click(object sender, EventArgs e)
+        {
+            textBox1.Text = textBox1.Text + 5;
+        }
+
+        private void button14_Click(object sender, EventArgs e)
+        {
+            textBox1.Text = textBox1.Text + 7;
+        }
+
+        private void button19_Click(object sender, EventArgs e)
+        {
+            a = float.Parse(textBox1.Text);
+            textBox1.Clear();
+            oper = 7;
+            label1.Text = a.ToString() + "+";
+            znak = true;
+        }
+
+        private void button18_Click(object sender, EventArgs e)
+        {
+            textBox1.Text = textBox1.Text + 8;
+        }
+
+        private void button8_Click(object sender, EventArgs e)
+        {
+            calculate();
+            label1.Text = "";
+        }
+
+        private void button1_Click(object sender, EventArgs e)
+        {
+            textBox1.Text = "";
+            label1.Text = "";
+        }
+
+        private void button2_Click(object sender, EventArgs e)
+        {
+            int lenght = textBox1.Text.Length - 1;
+            string text = textBox1.Text;
+            textBox1.Clear();
+            for (int i = 0; i < lenght; i++)
+            {
+                textBox1.Text = textBox1.Text + text[i];
+            }
+        }
+
+        private void textBox1_TextChanged(object sender, EventArgs e)
+        {
+
+        }
+
+        private void label1_Click(object sender, EventArgs e)
+        {
+
+        }
+
+        private void button4_Click(object sender, EventArgs e)
+        {
+            a = float.Parse(textBox1.Text);
+            textBox1.Clear();
+            oper = 1;
+            label1.Text = a.ToString() + "+";
+            znak = true;
+        }
+
+        private void button17_Click(object sender, EventArgs e)
+        {
+            textBox1.Text = textBox1.Text + 9;
+        }
+    }
+}

Form1.resx

@@ -0,0 +1,120 @@
+<?xml version="1.0" encoding="utf-8"?>
+<root>
+  <!-- 
+    Microsoft ResX Schema 
+    
+    Version 2.0
+    
+    The primary goals of this format is to allow a simple XML format 
+    that is mostly human readable. The generation and parsing of the 
+    various data types are done through the TypeConverter classes 
+    associated with the data types.
+    
+    Example:
+    
+    ... ado.net/XML headers & schema ...
+    <resheader name="resmimetype">text/microsoft-resx</resheader>
+    <resheader name="version">2.0</resheader>
+    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
+    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
+    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
+    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
+    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
+        <value>[base64 mime encoded serialized .NET Framework object]</value>
+    </data>
+    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
+        <comment>This is a comment</comment>
+    </data>
+                
+    There are any number of "resheader" rows that contain simple 
+    name/value pairs.
+    
+    Each data row contains a name, and value. The row also contains a 
+    type or mimetype. Type corresponds to a .NET class that support 
+    text/value conversion through the TypeConverter architecture. 
+    Classes that don't support this are serialized and stored with the 
+    mimetype set.
+    
+    The mimetype is used for serialized objects, and tells the 
+    ResXResourceReader how to depersist the object. This is currently not 
+    extensible. For a given mimetype the value must be set accordingly:
+    
+    Note - application/x-microsoft.net.object.binary.base64 is the format 
+    that the ResXResourceWriter will generate, however the reader can 
+    read any of the formats listed below.
+    
+    mimetype: application/x-microsoft.net.object.binary.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Binary.BinaryFormatter
+            : and then encoded with base64 encoding.
+    
+    mimetype: application/x-microsoft.net.object.soap.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.bytearray.base64
+    value   : The object must be serialized into a byte array 
+            : using a System.ComponentModel.TypeConverter
+            : and then encoded with base64 encoding.
+    -->
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:import namespace="http://www.w3.org/XML/1998/namespace" />
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" use="required" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+              <xsd:attribute ref="xml:space" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+</root>

Program.cs

@@ -0,0 +1,22 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using System.Windows.Forms;
+
+namespace Zharushkin_calculator2
+{
+    static class Program
+    {
+        /// <summary>
+        /// Главная точка входа для приложения.
+        /// </summary>
+        [STAThread]
+        static void Main()
+        {
+            Application.EnableVisualStyles();
+            Application.SetCompatibleTextRenderingDefault(false);
+            Application.Run(new Form1());
+        }
+    }
+}

Properties/AssemblyInfo.cs

@@ -0,0 +1,36 @@
+using System.Reflection;
+using System.Runtime.CompilerServices;
+using System.Runtime.InteropServices;
+
+// Общие сведения об этой сборке предоставляются следующим набором
+// набора атрибутов. Измените значения этих атрибутов для изменения сведений,
+// связанных со сборкой.
+[assembly: AssemblyTitle("Zharushkin_calculator2")]
+[assembly: AssemblyDescription("")]
+[assembly: AssemblyConfiguration("")]
+[assembly: AssemblyCompany("")]
+[assembly: AssemblyProduct("Zharushkin_calculator2")]
+[assembly: AssemblyCopyright("Copyright ©  2021")]
+[assembly: AssemblyTrademark("")]
+[assembly: AssemblyCulture("")]
+
+// Установка значения False для параметра ComVisible делает типы в этой сборке невидимыми
+// для компонентов COM. Если необходимо обратиться к типу в этой сборке через
+// COM, следует установить атрибут ComVisible в TRUE для этого типа.
+[assembly: ComVisible(false)]
+
+// Следующий GUID служит для идентификации библиотеки типов, если этот проект будет видимым для COM
+[assembly: Guid("84d66e30-b4d5-43f5-91e0-f272acffa1d3")]
+
+// Сведения о версии сборки состоят из указанных ниже четырех значений:
+//
+//      Основной номер версии
+//      Дополнительный номер версии
+//      Номер сборки
+//      Редакция
+//
+// Можно задать все значения или принять номера сборки и редакции по умолчанию 
+// используя "*", как показано ниже:
+// [assembly: AssemblyVersion("1.0.*")]
+[assembly: AssemblyVersion("1.0.0.0")]
+[assembly: AssemblyFileVersion("1.0.0.0")]

Properties/Resources.Designer.cs

@@ -0,0 +1,71 @@
+//------------------------------------------------------------------------------
+// <auto-generated>
+//     Этот код создан программным средством.
+//     Версия среды выполнения: 4.0.30319.42000
+//
+//     Изменения в этом файле могут привести к неправильному поведению и будут утрачены, если
+//     код создан повторно.
+// </auto-generated>
+//------------------------------------------------------------------------------
+
+namespace Zharushkin_calculator2.Properties
+{
+
+
+    /// <summary>
+    ///   Класс ресурсов со строгим типом для поиска локализованных строк и пр.
+    /// </summary>
+    // Этот класс был автоматически создан при помощи StronglyTypedResourceBuilder
+    // класс с помощью таких средств, как ResGen или Visual Studio.
+    // Для добавления или удаления члена измените файл .ResX, а затем перезапустите ResGen
+    // с параметром /str или заново постройте свой VS-проект.
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("System.Resources.Tools.StronglyTypedResourceBuilder", "4.0.0.0")]
+    [global::System.Diagnostics.DebuggerNonUserCodeAttribute()]
+    [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
+    internal class Resources
+    {
+
+        private static global::System.Resources.ResourceManager resourceMan;
+
+        private static global::System.Globalization.CultureInfo resourceCulture;
+
+        [global::System.Diagnostics.CodeAnalysis.SuppressMessageAttribute("Microsoft.Performance", "CA1811:AvoidUncalledPrivateCode")]
+        internal Resources()
+        {
+        }
+
+        /// <summary>
+        ///   Возврат кэшированного экземпляра ResourceManager, используемого этим классом.
+        /// </summary>
+        [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)]
+        internal static global::System.Resources.ResourceManager ResourceManager
+        {
+            get
+            {
+                if ((resourceMan == null))
+                {
+                    global::System.Resources.ResourceManager temp = new global::System.Resources.ResourceManager("Zharushkin_calculator2.Properties.Resources", typeof(Resources).Assembly);
+                    resourceMan = temp;
+                }
+                return resourceMan;
+            }
+        }
+
+        /// <summary>
+        ///   Переопределяет свойство CurrentUICulture текущего потока для всех
+        ///   подстановки ресурсов с помощью этого класса ресурсов со строгим типом.
+        /// </summary>
+        [global::System.ComponentModel.EditorBrowsableAttribute(global::System.ComponentModel.EditorBrowsableState.Advanced)]
+        internal static global::System.Globalization.CultureInfo Culture
+        {
+            get
+            {
+                return resourceCulture;
+            }
+            set
+            {
+                resourceCulture = value;
+            }
+        }
+    }
+}

Properties/Resources.resx

@@ -0,0 +1,117 @@
+<?xml version="1.0" encoding="utf-8"?>
+<root>
+  <!-- 
+    Microsoft ResX Schema 
+    
+    Version 2.0
+    
+    The primary goals of this format is to allow a simple XML format 
+    that is mostly human readable. The generation and parsing of the 
+    various data types are done through the TypeConverter classes 
+    associated with the data types.
+    
+    Example:
+    
+    ... ado.net/XML headers & schema ...
+    <resheader name="resmimetype">text/microsoft-resx</resheader>
+    <resheader name="version">2.0</resheader>
+    <resheader name="reader">System.Resources.ResXResourceReader, System.Windows.Forms, ...</resheader>
+    <resheader name="writer">System.Resources.ResXResourceWriter, System.Windows.Forms, ...</resheader>
+    <data name="Name1"><value>this is my long string</value><comment>this is a comment</comment></data>
+    <data name="Color1" type="System.Drawing.Color, System.Drawing">Blue</data>
+    <data name="Bitmap1" mimetype="application/x-microsoft.net.object.binary.base64">
+        <value>[base64 mime encoded serialized .NET Framework object]</value>
+    </data>
+    <data name="Icon1" type="System.Drawing.Icon, System.Drawing" mimetype="application/x-microsoft.net.object.bytearray.base64">
+        <value>[base64 mime encoded string representing a byte array form of the .NET Framework object]</value>
+        <comment>This is a comment</comment>
+    </data>
+                
+    There are any number of "resheader" rows that contain simple 
+    name/value pairs.
+    
+    Each data row contains a name, and value. The row also contains a 
+    type or mimetype. Type corresponds to a .NET class that support 
+    text/value conversion through the TypeConverter architecture. 
+    Classes that don't support this are serialized and stored with the 
+    mimetype set.
+    
+    The mimetype is used for serialized objects, and tells the 
+    ResXResourceReader how to depersist the object. This is currently not 
+    extensible. For a given mimetype the value must be set accordingly:
+    
+    Note - application/x-microsoft.net.object.binary.base64 is the format 
+    that the ResXResourceWriter will generate, however the reader can 
+    read any of the formats listed below.
+    
+    mimetype: application/x-microsoft.net.object.binary.base64
+    value   : The object must be serialized with 
+            : System.Serialization.Formatters.Binary.BinaryFormatter
+            : and then encoded with base64 encoding.
+    
+    mimetype: application/x-microsoft.net.object.soap.base64
+    value   : The object must be serialized with 
+            : System.Runtime.Serialization.Formatters.Soap.SoapFormatter
+            : and then encoded with base64 encoding.
+
+    mimetype: application/x-microsoft.net.object.bytearray.base64
+    value   : The object must be serialized into a byte array 
+            : using a System.ComponentModel.TypeConverter
+            : and then encoded with base64 encoding.
+    -->
+  <xsd:schema id="root" xmlns="" xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:msdata="urn:schemas-microsoft-com:xml-msdata">
+    <xsd:element name="root" msdata:IsDataSet="true">
+      <xsd:complexType>
+        <xsd:choice maxOccurs="unbounded">
+          <xsd:element name="metadata">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" />
+              <xsd:attribute name="type" type="xsd:string" />
+              <xsd:attribute name="mimetype" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="assembly">
+            <xsd:complexType>
+              <xsd:attribute name="alias" type="xsd:string" />
+              <xsd:attribute name="name" type="xsd:string" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="data">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+                <xsd:element name="comment" type="xsd:string" minOccurs="0" msdata:Ordinal="2" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" msdata:Ordinal="1" />
+              <xsd:attribute name="type" type="xsd:string" msdata:Ordinal="3" />
+              <xsd:attribute name="mimetype" type="xsd:string" msdata:Ordinal="4" />
+            </xsd:complexType>
+          </xsd:element>
+          <xsd:element name="resheader">
+            <xsd:complexType>
+              <xsd:sequence>
+                <xsd:element name="value" type="xsd:string" minOccurs="0" msdata:Ordinal="1" />
+              </xsd:sequence>
+              <xsd:attribute name="name" type="xsd:string" use="required" />
+            </xsd:complexType>
+          </xsd:element>
+        </xsd:choice>
+      </xsd:complexType>
+    </xsd:element>
+  </xsd:schema>
+  <resheader name="resmimetype">
+    <value>text/microsoft-resx</value>
+  </resheader>
+  <resheader name="version">
+    <value>2.0</value>
+  </resheader>
+  <resheader name="reader">
+    <value>System.Resources.ResXResourceReader, System.Windows.Forms, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+  <resheader name="writer">
+    <value>System.Resources.ResXResourceWriter, System.Windows.Forms, Version=2.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089</value>
+  </resheader>
+</root>

Properties/Settings.Designer.cs

@@ -0,0 +1,30 @@
+//------------------------------------------------------------------------------
+// <auto-generated>
+//     This code was generated by a tool.
+//     Runtime Version:4.0.30319.42000
+//
+//     Changes to this file may cause incorrect behavior and will be lost if
+//     the code is regenerated.
+// </auto-generated>
+//------------------------------------------------------------------------------
+
+namespace Zharushkin_calculator2.Properties
+{
+
+
+    [global::System.Runtime.CompilerServices.CompilerGeneratedAttribute()]
+    [global::System.CodeDom.Compiler.GeneratedCodeAttribute("Microsoft.VisualStudio.Editors.SettingsDesigner.SettingsSingleFileGenerator", "11.0.0.0")]
+    internal sealed partial class Settings : global::System.Configuration.ApplicationSettingsBase
+    {
+
+        private static Settings defaultInstance = ((Settings)(global::System.Configuration.ApplicationSettingsBase.Synchronized(new Settings())));
+
+        public static Settings Default
+        {
+            get
+            {
+                return defaultInstance;
+            }
+        }
+    }
+}

Properties/Settings.settings

@@ -0,0 +1,7 @@
+<?xml version='1.0' encoding='utf-8'?>
+<SettingsFile xmlns="http://schemas.microsoft.com/VisualStudio/2004/01/settings" CurrentProfile="(Default)">
+  <Profiles>
+    <Profile Name="(Default)" />
+  </Profiles>
+  <Settings />
+</SettingsFile>

Zharushkin_calculator2.csproj

@@ -0,0 +1,83 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="15.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <Import Project="$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props" Condition="Exists('$(MSBuildExtensionsPath)\$(MSBuildToolsVersion)\Microsoft.Common.props')" />
+  <PropertyGroup>
+    <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
+    <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
+    <ProjectGuid>{84D66E30-B4D5-43F5-91E0-F272ACFFA1D3}</ProjectGuid>
+    <OutputType>WinExe</OutputType>
+    <RootNamespace>Zharushkin_calculator2</RootNamespace>
+    <AssemblyName>Zharushkin_calculator2</AssemblyName>
+    <TargetFrameworkVersion>v4.7.2</TargetFrameworkVersion>
+    <FileAlignment>512</FileAlignment>
+    <AutoGenerateBindingRedirects>true</AutoGenerateBindingRedirects>
+    <Deterministic>true</Deterministic>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Debug|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugSymbols>true</DebugSymbols>
+    <DebugType>full</DebugType>
+    <Optimize>false</Optimize>
+    <OutputPath>bin\Debug\</OutputPath>
+    <DefineConstants>DEBUG;TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <PropertyGroup Condition=" '$(Configuration)|$(Platform)' == 'Release|AnyCPU' ">
+    <PlatformTarget>AnyCPU</PlatformTarget>
+    <DebugType>pdbonly</DebugType>
+    <Optimize>true</Optimize>
+    <OutputPath>bin\Release\</OutputPath>
+    <DefineConstants>TRACE</DefineConstants>
+    <ErrorReport>prompt</ErrorReport>
+    <WarningLevel>4</WarningLevel>
+  </PropertyGroup>
+  <ItemGroup>
+    <Reference Include="System" />
+    <Reference Include="System.Core" />
+    <Reference Include="System.Xml.Linq" />
+    <Reference Include="System.Data.DataSetExtensions" />
+    <Reference Include="Microsoft.CSharp" />
+    <Reference Include="System.Data" />
+    <Reference Include="System.Deployment" />
+    <Reference Include="System.Drawing" />
+    <Reference Include="System.Net.Http" />
+    <Reference Include="System.Windows.Forms" />
+    <Reference Include="System.Xml" />
+  </ItemGroup>
+  <ItemGroup>
+    <Compile Include="Form1.cs">
+      <SubType>Form</SubType>
+    </Compile>
+    <Compile Include="Form1.Designer.cs">
+      <DependentUpon>Form1.cs</DependentUpon>
+    </Compile>
+    <Compile Include="Program.cs" />
+    <Compile Include="Properties\AssemblyInfo.cs" />
+    <EmbeddedResource Include="Form1.resx">
+      <DependentUpon>Form1.cs</DependentUpon>
+    </EmbeddedResource>
+    <EmbeddedResource Include="Properties\Resources.resx">
+      <Generator>ResXFileCodeGenerator</Generator>
+      <LastGenOutput>Resources.Designer.cs</LastGenOutput>
+      <SubType>Designer</SubType>
+    </EmbeddedResource>
+    <Compile Include="Properties\Resources.Designer.cs">
+      <AutoGen>True</AutoGen>
+      <DependentUpon>Resources.resx</DependentUpon>
+    </Compile>
+    <None Include="Properties\Settings.settings">
+      <Generator>SettingsSingleFileGenerator</Generator>
+      <LastGenOutput>Settings.Designer.cs</LastGenOutput>
+    </None>
+    <Compile Include="Properties\Settings.Designer.cs">
+      <AutoGen>True</AutoGen>
+      <DependentUpon>Settings.settings</DependentUpon>
+      <DesignTimeSharedInput>True</DesignTimeSharedInput>
+    </Compile>
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="App.config" />
+  </ItemGroup>
+  <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
+</Project>

Zharushkin_calculator2.sln

@@ -0,0 +1,25 @@
+
+Microsoft Visual Studio Solution File, Format Version 12.00
+# Visual Studio Version 16
+VisualStudioVersion = 16.0.29609.76
+MinimumVisualStudioVersion = 10.0.40219.1
+Project("{FAE04EC0-301F-11D3-BF4B-00C04F79EFBC}") = "Zharushkin_calculator2", "Zharushkin_calculator2.csproj", "{84D66E30-B4D5-43F5-91E0-F272ACFFA1D3}"
+EndProject
+Global
+	GlobalSection(SolutionConfigurationPlatforms) = preSolution
+		Debug|Any CPU = Debug|Any CPU
+		Release|Any CPU = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(ProjectConfigurationPlatforms) = postSolution
+		{84D66E30-B4D5-43F5-91E0-F272ACFFA1D3}.Debug|Any CPU.ActiveCfg = Debug|Any CPU
+		{84D66E30-B4D5-43F5-91E0-F272ACFFA1D3}.Debug|Any CPU.Build.0 = Debug|Any CPU
+		{84D66E30-B4D5-43F5-91E0-F272ACFFA1D3}.Release|Any CPU.ActiveCfg = Release|Any CPU
+		{84D66E30-B4D5-43F5-91E0-F272ACFFA1D3}.Release|Any CPU.Build.0 = Release|Any CPU
+	EndGlobalSection
+	GlobalSection(SolutionProperties) = preSolution
+		HideSolutionNode = FALSE
+	EndGlobalSection
+	GlobalSection(ExtensibilityGlobals) = postSolution
+		SolutionGuid = {83CD1F81-80F0-4627-B9E3-03E106C5E471}
+	EndGlobalSection
+EndGlobal