1 using System;
 2 
 3 using System.Windows.Forms;
 4 
 5 namespace WindowsFormsApp1
 6 {
 7     public partial class Form1 : Form
 8     {
 9         public Form1()
10         {
11             InitializeComponent();
12         }
13 
14         private void button1_Click(object sender, EventArgs e)
15         {
16             string num_str;
17             num_str = textBox1.Text;
18             double num_0 = double.Parse(num_str);
19             num_str = textBox2.Text;
20             double num_1 = double.Parse(num_str);
21 
22             label4.Text = "" + num_0 * num_1;
23         }
24     }
25 }