все, лаба 4 работает

lab4/Form1.Designer.cs

@@ -31,6 +31,19 @@
             dateTimePicker = new DateTimePicker();
             label1 = new Label();
             numericUpDown = new NumericUpDown();
+            button = new Button();
+            comboBoxFormats = new ComboBox();
+            dateTimePicker1 = new DateTimePicker();
+            dateTimePicker2 = new DateTimePicker();
+            label2 = new Label();
+            label3 = new Label();
+            buttonBrth = new Button();
+            label4 = new Label();
+            dateTimePicker3 = new DateTimePicker();
+            dateTimePicker4 = new DateTimePicker();
+            textBox1 = new TextBox();
+            btnToString = new Button();
+            btnToDate = new Button();
             ((System.ComponentModel.ISupportInitialize)numericUpDown).BeginInit();
             SuspendLayout();
             // 
@@ -57,11 +70,133 @@
             numericUpDown.Size = new Size(150, 27);
             numericUpDown.TabIndex = 2;
             // 
+            // button
+            // 
+            button.Location = new Point(644, 10);
+            button.Name = "button";
+            button.Size = new Size(312, 29);
+            button.TabIndex = 3;
+            button.Text = "вывести в определенном вормате";
+            button.UseVisualStyleBackColor = true;
+            button.Click += button_Click;
+            // 
+            // comboBoxFormats
+            // 
+            comboBoxFormats.FormattingEnabled = true;
+            comboBoxFormats.Location = new Point(466, 11);
+            comboBoxFormats.Name = "comboBoxFormats";
+            comboBoxFormats.Size = new Size(151, 28);
+            comboBoxFormats.TabIndex = 4;
+            // 
+            // dateTimePicker1
+            // 
+            dateTimePicker1.Location = new Point(12, 193);
+            dateTimePicker1.Name = "dateTimePicker1";
+            dateTimePicker1.Size = new Size(250, 27);
+            dateTimePicker1.TabIndex = 5;
+            // 
+            // dateTimePicker2
+            // 
+            dateTimePicker2.Location = new Point(335, 193);
+            dateTimePicker2.Name = "dateTimePicker2";
+            dateTimePicker2.Size = new Size(250, 27);
+            dateTimePicker2.TabIndex = 6;
+            // 
+            // label2
+            // 
+            label2.AutoSize = true;
+            label2.Location = new Point(15, 229);
+            label2.Name = "label2";
+            label2.Size = new Size(150, 20);
+            label2.TabIndex = 7;
+            label2.Text = "Ваш день рождения";
+            // 
+            // label3
+            // 
+            label3.AutoSize = true;
+            label3.Location = new Point(335, 229);
+            label3.Name = "label3";
+            label3.Size = new Size(161, 20);
+            label3.TabIndex = 8;
+            label3.Text = "День рождения друга";
+            // 
+            // buttonBrth
+            // 
+            buttonBrth.Location = new Point(690, 195);
+            buttonBrth.Name = "buttonBrth";
+            buttonBrth.Size = new Size(94, 29);
+            buttonBrth.TabIndex = 9;
+            buttonBrth.Text = "рассчитать";
+            buttonBrth.UseVisualStyleBackColor = true;
+            buttonBrth.Click += buttonBrth_Click;
+            // 
+            // label4
+            // 
+            label4.AutoSize = true;
+            label4.Location = new Point(199, 280);
+            label4.Name = "label4";
+            label4.Size = new Size(0, 20);
+            label4.TabIndex = 10;
+            // 
+            // dateTimePicker3
+            // 
+            dateTimePicker3.Location = new Point(12, 420);
+            dateTimePicker3.Name = "dateTimePicker3";
+            dateTimePicker3.Size = new Size(250, 27);
+            dateTimePicker3.TabIndex = 11;
+            // 
+            // dateTimePicker4
+            // 
+            dateTimePicker4.Location = new Point(706, 420);
+            dateTimePicker4.Name = "dateTimePicker4";
+            dateTimePicker4.Size = new Size(250, 27);
+            dateTimePicker4.TabIndex = 12;
+            // 
+            // textBox1
+            // 
+            textBox1.Location = new Point(382, 422);
+            textBox1.Name = "textBox1";
+            textBox1.Size = new Size(235, 27);
+            textBox1.TabIndex = 13;
+            // 
+            // btnToString
+            // 
+            btnToString.Location = new Point(259, 506);
+            btnToString.Name = "btnToString";
+            btnToString.Size = new Size(94, 29);
+            btnToString.TabIndex = 14;
+            btnToString.Text = "в строку";
+            btnToString.UseVisualStyleBackColor = true;
+            btnToString.Click += btnToString_Click;
+            // 
+            // btnToDate
+            // 
+            btnToDate.Location = new Point(620, 506);
+            btnToDate.Name = "btnToDate";
+            btnToDate.Size = new Size(152, 29);
+            btnToDate.TabIndex = 15;
+            btnToDate.Text = "обратно в дату";
+            btnToDate.UseVisualStyleBackColor = true;
+            btnToDate.Click += btnToDate_Click;
+            // 
             // Form1
             // 
             AutoScaleDimensions = new SizeF(8F, 20F);
             AutoScaleMode = AutoScaleMode.Font;
-            ClientSize = new Size(800, 450);
+            ClientSize = new Size(977, 612);
+            Controls.Add(btnToDate);
+            Controls.Add(btnToString);
+            Controls.Add(textBox1);
+            Controls.Add(dateTimePicker4);
+            Controls.Add(dateTimePicker3);
+            Controls.Add(label4);
+            Controls.Add(buttonBrth);
+            Controls.Add(label3);
+            Controls.Add(label2);
+            Controls.Add(dateTimePicker2);
+            Controls.Add(dateTimePicker1);
+            Controls.Add(comboBoxFormats);
+            Controls.Add(button);
             Controls.Add(numericUpDown);
             Controls.Add(label1);
             Controls.Add(dateTimePicker);
@@ -77,5 +212,18 @@
         private DateTimePicker dateTimePicker;
         private Label label1;
         private NumericUpDown numericUpDown;
+        private Button button;
+        private ComboBox comboBoxFormats;
+        private DateTimePicker dateTimePicker1;
+        private DateTimePicker dateTimePicker2;
+        private Label label2;
+        private Label label3;
+        private Button buttonBrth;
+        private Label label4;
+        private DateTimePicker dateTimePicker3;
+        private DateTimePicker dateTimePicker4;
+        private TextBox textBox1;
+        private Button btnToString;
+        private Button btnToDate;
     }
 }

lab4/Form1.cs

@@ -5,6 +5,8 @@ namespace lab4
         public Form1()
         {
             InitializeComponent();
+            //comboBoxFormats.Items.AddRange(new string[] { "Ïîëíàÿ äàòà è âðåìÿ", "Êîðîòêàÿ äàòà", "Äëèííàÿ äàòà", "Òîëüêî âðåìÿ", "Ãîä è ìåñÿö" });
+            comboBoxFormats.Items.AddRange(new string[] { "F", "d", "D", "T", "Y" });
         }
 
         private void dateTimePicker_ValueChanged(object sender, EventArgs e)
@@ -13,9 +15,82 @@ namespace lab4
             int hours = Convert.ToInt32(numericUpDown.Value);
             if (date != null)
             {
-                label1.Text = "Âû âûáðàëè: " + date.ToString() + " â " + date.Hour.ToString() + " ÷àñîâ è " + date.Minute.ToString() + " ìèíóò";
+                label1.Text = "Âû âûáðàëè: "
+                    + date.ToString()
+                    + " â "
+                    + date.Hour.ToString()
+                    + " ÷àñîâ è "
+                    + date.Minute.ToString()
+                    + " ìèíóò";
                 label1.Text += $"\nÀ åñëè áû âû âûáðàëè âðåìÿ ÷åðåç {hours} ÷àñîâ è ñòîëüêî æå äíåé, òî áûëî áû "
-                    + date.AddHours(hours).Hour.ToString() + " ÷àñîâ è " + date.AddDays(hours).Day.ToString() + " äíåé ìåñÿöà: " + date.AddDays(hours).Month.ToString();
+                    + date.AddHours(hours).Hour.ToString()
+                    + " ÷àñîâ è "
+                    + date.AddDays(hours).Day.ToString()
+                    + " äíåé ìåñÿöà: "
+                    + date.AddDays(hours).Month.ToString();
+            }
+        }
+
+        private void button_Click(object sender, EventArgs e)
+        {
+            DateTime date = dateTimePicker.Value;
+            if (comboBoxFormats.SelectedIndex != -1)
+            {
+                label1.Text = "Äàòà â âûáðàííîì ôîðìàòå: " + date.ToString(comboBoxFormats.SelectedItem?.ToString());
+            }
+        }
+
+        private void buttonBrth_Click(object sender, EventArgs e)
+        {
+            DateTime yourB = dateTimePicker1.Value;
+            DateTime friendBrth = dateTimePicker2.Value;
+
+            if (friendBrth < yourB)
+            {
+                yourB.AddYears(-friendBrth.Year);
+                yourB.AddMonths(-friendBrth.Month);
+                yourB.AddDays(-friendBrth.Day);
+                label4.Text = "Âàø äðóã ñòàðøå âàñ íà "
+                    + yourB.AddYears(-friendBrth.Year).Year.ToString()
+                    + " ëåò, íà "
+                    + yourB.AddMonths(-friendBrth.Month).Month.ToString()
+                    + " ìåñÿöåâ è íà "
+                    + yourB.AddDays(-friendBrth.Day).Day.ToString()
+                    + " äíåé";
+            }
+            else
+            {
+                label4.Text = "Âû ñòàðøå äðóãà íà "
+                    + friendBrth.AddYears(-yourB.Year).Year.ToString()
+                    + " ëåò, íà "
+                    + friendBrth.AddMonths(-yourB.Month).Month.ToString()
+                    + " ìåñÿöåâ è íà "
+                    + friendBrth.AddDays(-yourB.Day).Day.ToString()
+                    + " äíåé";
+            }
+        }
+
+        private void btnToString_Click(object sender, EventArgs e)
+        {
+            DateTime date = dateTimePicker3.Value;
+            textBox1.Text = date.ToString();
+        }
+
+        private void btnToDate_Click(object sender, EventArgs e)
+        {
+            if(textBox1.Text != null)
+            {
+               string dateStr = textBox1.Text;
+                try
+                {
+                    DateTime date = DateTime.Parse(dateStr);
+                    dateTimePicker4.Value = date;
+                }
+                catch (Exception)
+                {
+
+                    throw;
+                }
             }
         }
     }