1. Age Restriction

namespace BookShop
{
    using BookShop.Data;
    using BookShop.Initializer;
    using BookShop.Models;
    using Microsoft.EntityFrameworkCore;
    using System;
    using System.Globalization;
    using System.Linq;
    using System.Text;

    public class StartUp
    {
        public static void Main()
        {
            using (var context = new BookShopContext())
            {
                //DbInitializer.ResetDatabase(db);

                //1.Age Restriction
                string command = Console.ReadLine();
                string ageRestricted = GetBooksByAgeRestriction(context, command);
                Console.WriteLine(ageRestricted);
            }
        }

        public static string GetBooksByAgeRestriction(BookShopContext context, string command)
        {
            var books = context.Books.OrderBy(x => x.Title).ToList();

            string result = string.Empty;

            int compare = -1;

            switch (command.ToLower())
            {
                case "minor":
                    compare = 0;
                   var minors = context.Books
                        .Where(x => (int)x.AgeRestriction == compare)
                        .OrderBy(x => x.Title)
                        .Select(x => x.Title)
                        .ToList();

                    result = string.Join(Environment.NewLine, minors);

                    break;
                case "teen":
                    compare = 1;
                    var teens = context.Books
                        .Where(x => (int)x.AgeRestriction == compare)
                        .OrderBy(x => x.Title)
                        .Select(x => x.Title)
                        .ToList();

                    result = string.Join(Environment.NewLine, teens);

                    break;
                case "adult":
                    compare = 2;
                    var adults = context.Books
                        .Where(x => (int)x.AgeRestriction == compare)
                        .OrderBy(x => x.Title)
                        .Select(x => x.Title)
                        .ToList();

                    result = string.Join(Environment.NewLine, adults);
                    break;
                default:
                    break;
            }
            return result;
        }

    }
}