Дерево решений

namespace ConsoleApp3
{
    class Program
    {
        static void Main(string[] args)
        {
            var decisionTree = MainDecisionTree();
 
            var client = new Client();
 
            Console.WriteLine("Do you want a book? true/false");
            client.Answer[0] = bool.Parse(Console.ReadLine());
            Console.WriteLine("Do you like it? true/false");
            client.Answer[1] = bool.Parse(Console.ReadLine());
            Console.WriteLine("Are you sure? true/false");
            client.Answer[2] = bool.Parse(Console.ReadLine());
 
            decisionTree.Evaluate(client);
 
            Console.WriteLine("Press any key...");
            Console.ReadKey();
        }
 
        private static DecisionQuery MainDecisionTree()
        {
            //Decision 2
            var wantBranch = new DecisionQuery
            {
                Title = "Do you want a book?",
                Test = (client) => client.Answer[0],
                Positive = new DecisionResult { Result = true },
                Negative = new DecisionResult { Result = false }
            };
 
            //Decision 1
            var deserveBranch = new DecisionQuery
            {
                Title = "Do you like it?",
                Test = (client) => client.Answer[1],
                Positive = wantBranch,
                Negative = new DecisionResult { Result = false }
            };
 
 
            //Decision 0
            var sureBranch = new DecisionQuery
            {
                Title = "Are you sure?",
                Test = (client) => client.Answer[2],
                Positive = deserveBranch,
                Negative = new DecisionResult { Result = false }
            };
 
            return sureBranch;
        }
    }
 
    public class DecisionResult : Decision
    {
        public bool Result { get; set; }
 
        public override void Evaluate(Client client)
        {
            Console.WriteLine("\r\nThe result: {0}", Result ? "Buy it" : "You need to wait");
        }
    }
 
    public class DecisionQuery : Decision
    {
        public string Title { get; set; }
        public Decision Positive { get; set; }
        public Decision Negative { get; set; }
        public Func<Client, bool> Test { get; set; }
 
        public override void Evaluate(Client client)
        {
            bool result = this.Test(client);
            string resultAsString = result ? "yes" : "no";
 
            Console.WriteLine($"\t- {this.Title}? {resultAsString}");
 
            if (result) this.Positive.Evaluate(client);
            else this.Negative.Evaluate(client);
        }
    }
 
    public abstract class Decision
    {
        public abstract void Evaluate(Client client);
    }
 
    public class Client
    {
        public bool[] Answer { get; set; } = new bool[3];
    }
}