Simple LINQ, lambda and string formatting example.

Program.cs

using System;
using System.Collections.Generic;
using System.IO;
using Microsoft.VisualBasic.FileIO;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System.Linq;

namespace csharp_test
{
    class Program
    {
        class Book { //Inner Class
            public Book(string title, string publisher) {
                this.Title = title;
                this.Publisher = publisher;
            }
            public int Id { get; set; }
            public string Title { get; set; }  
            public string Publisher { get; set; }

            public override string ToString()
            {
                return $"Title:{Title}, Publisher:{Publisher}";
            }
        }
        static void Main(string[] args)
        {
          List<Book> books = new List<Book>();
          books.Add(new Book("A Book Title1","Publisher"));  
          books.Add(new Book("A Book Title0","Publisher"));  
          books.Add(new Book("The Title2","Publisher"));  
          books.Add(new Book("A Book Title3","Another one"));  
          books.Add(new Book("title","Third one"));  
          var subset = books.Where(book =>  book.Title.StartsWith('A') && book.Publisher == "Publisher").OrderBy(b => b.Title).ToList();
          foreach(var b in subset) {
              System.Console.WriteLine(b.ToString());
          }

          Format((string str) => {
            System.Console.WriteLine("we received: "+str);
          });
        }

        static void Format(Action<string> act) {
            act("testing it");
        }

       
    }
}