Объясните код программы - C#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;
 
namespace WindowsFormsApplication3
{
    public partial class Form1 : Form
    {
        public Form1()
        {
            InitializeComponent();}
            
    private double stringadd(int i, int state) {
dataGridView1.Rows[i].Cells[0].Value = string.Format("{0}", i + 1);
dataGridView1.Rows[i].Cells[1].Value = string.Format("{0}", state);
//генерируем ррсч
double rrs4;
rrs4 = myRandom.NextDouble();
dataGridView1.Rows[i].Cells[2].Value = string.Format("{0}", rrs4);
return rrs4;}
private double lsr(int _count)
{ double p2111 = 0.163;
double p1111 = 0.103;
double p2011 = 0.228;
double p1000 = 0.014;
double _lsr = 0; 
for (int i = 0; i < _count; i++) {
    if (dataGridView1.Rows[i].Cells[1].FormattedValue.ToString() == "2111")
_lsr = _lsr + p2111;
if (dataGridView1.Rows[i].Cells[1].FormattedValue.ToString() == "1111")
_lsr = _lsr + p1111;
if (dataGridView1.Rows[i].Cells[1].FormattedValue.ToString() == "2011")
_lsr = _lsr + 2*p2011;
if (dataGridView1.Rows[i].Cells[1].FormattedValue.ToString() == "1000")
_lsr = _lsr + 2*p1000;
} return _lsr; }
private Random myRandom = new Random();
 
        private void button1_Click(object sender, EventArgs e)
        {
        dataGridView1.Rows.Clear(); //чистим таблицу
int _count; //количество испытаний вводимое с клавы
int.TryParse(textBox1.Text, out _count);
dataGridView1.Rows.Add(_count); //увеличиваем таблицу насколько нужно
int state = 2000; //переменная текущего состояния системы
double rrs4;
for (int i = 0; i < _count; i++)
{ switch (state)
{ case 2000:
rrs4 = stringadd(i, state);
state = 1000; break;
case 1000:
rrs4 = stringadd(i, state);
state = 2010; break;
case 2010:
rrs4 = stringadd(i, state);
if (rrs4 <= 0.6) state = 1001;
else state = 1010; break;
case 1010:
rrs4 = stringadd(i, state);
if (rrs4 <= 0.6) state = 2011;
else state = 2110; break;
case 2011:
rrs4 = stringadd(i, state);
if (rrs4 <= 0.6) state = 1001;
else if (rrs4 < 0.24) state = 1010;
else state = 1011; break;
case 1011:
rrs4 = stringadd(i, state);
if (rrs4 <= 0.36) state = 2010;
else if (rrs4 < 0.24) state = 2011;
else if (rrs4 < 0.24) state = 2110;
else state = 2111; break;
case 1001:
rrs4 = stringadd(i, state);
if (rrs4 <= 0.6) state = 2010;
else state = 2011; break;
case 2111:
rrs4 = stringadd(i, state);
if (rrs4 <= 0.6) state = 1011;
else if (rrs4 < 0.24) state = 1110;
else state = 1111; break;
case 1111:
rrs4 = stringadd(i, state);
if (rrs4 <= 0.24) state = 2110;
else if (rrs4 < 0.6) state = 2111;
else state = 2211; break;
case 2211:
rrs4 = stringadd(i, state);
if (rrs4 <= 0.6) state = 1111;
else if (rrs4 < 0.24) state = 1010;
else state = 1011; break;
case 1011:
rrs4 = stringadd(i, state);
if (rrs4 <= 0.24) state = 2010;
else state = 2011; break; } }
double _lsr = lsr(_count);
textBox2.Text = string.Format("Вероятность блокировки Рбл: {0}", _lsr);
textBox3.Text = string.Format("Среднее время пребывания заявки в системе Wc: {0}", _lsr);
MessageBox.Show("Моделирование завершено", "Сообщение");}