C#字符串操作，可空类型，文档注释，嵌套类型

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Diagnostics;
namespace ConsoleApp2
{
    
    class Program
    {
        
        static void Main(string[] args)
        {
            string s1 = "hi there! this, is: a string.";
            char[] delimiter = { ' ', '!', ',', '.',':' };
            string[] words = s1.Split(delimiter, StringSplitOptions.RemoveEmptyEntries);
            foreach (string s in words)
            {
                Console.WriteLine(s);
            }
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Diagnostics;
namespace ConsoleApp2
{
    class Program
    {
        static void Main(string[] args)
        {
            string parseResultSummary;
            string stringFirst = "28";
            int intFirst;
            bool success = int.TryParse(stringFirst, out intFirst);
            parseResultSummary = success ? "was successfully pared" : "was not successfully parsed";
            Console.WriteLine("String {0} {1}",stringFirst,parseResultSummary);
            string stringSecOnd= "vt750";
            int intSecond;
            success = int.TryParse(stringSecond, out intSecond);
            parseResultSummary = success ? "was successfully parsed" : "was not successfully parsed";
            Console.WriteLine("String {0} {1}", stringSecond, parseResultSummary);
        }
    }
}

struct MyStruct{
        public int x;
        public int y;
        public MyStruct(int xVal,int yVal)
        {
            x = xVal;
            y = yVal;
        }
}

static void Main(string[] args)
{
            MyStruct? mSNull = new MyStruct(5, 10);
            Console.WriteLine(mSNull.Value.x);
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Diagnostics;
namespace ConsoleApp2
{
    class MyClass
    {
        class MyCounter
        {
            public int Count { get; private set; }
            public static MyCounter operator ++(MyCounter current)
            {
                current.Count++;
                return current;
            }
        }
        private MyCounter counter;//嵌套类类型的字段
        public MyClass() { counter = new MyCounter(); }//构造函数
        public int Incr() { return (counter++).Count; }//构造函数
        public int GetValue() { return counter.Count; }//获取计数值
    }
    class Program
    {
        static void Main()
        {
            MyClass mc = new MyClass();
            mc.Incr(); mc.Incr(); mc.Incr();
            mc.Incr(); mc.Incr(); mc.Incr();
            Console.WriteLine(mc.GetValue());
        }
    }
}

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Reflection;
using System.Runtime.CompilerServices;
using System.Diagnostics;
namespace ConsoleApp2
{
    class SomeClass//封闭类
    {
        int Field1 = 15, Field2 = 20;//封闭类的字段
        MyNested mn = null;//嵌套类的引用
        public void PrintMyMembers()
        {
            mn.PrintOuterMembers();//调用嵌套类中的方法
        }
        public SomeClass()//构造函数
        {
            mn = new MyNested(this);//创建嵌套类实例 this给封闭类型传递引用
        }

        class MyNested//嵌套类声明
        {
            SomeClass sc = null;//封闭类的引用
            public MyNested(SomeClass SC)//嵌套类的构造函数
            {
                sc = SC;//存储嵌套类的引用
            }
            public void PrintOuterMembers()
            {
                Console.WriteLine("Field1 : {0}",sc.Field1);//封闭字段
                Console.WriteLine("Field2 : {0}",sc.Field2);//封闭字段
            }
        }
    }
    class Program
    {
        static void Main()
        {
            SomeClass MySC = new SomeClass();
            MySC.PrintMyMembers();
        }
    }
}