dip_1.cs

using System;

namespace dip_1
{
    class Program
    {
        static void Main(string[] args)
        {
            var bakery = new Restaurant("Bakery");
            bakery.Cook("cookies");
        }
    }

    class Restaurant
    {
        public string Name { get; set; }

        private Oven Oven = new Oven();

        public Restaurant(string name)
        {
            this.Name = name;
        }

        public void Cook(string item)
        {
            this.Oven.LightGas();
            this.Oven.Bake(item);
            this.Oven.ExtinguishGas();
        }
    }

    class Oven
    {
        public bool On { get; set; }

        public void LightGas()
        {
            Console.WriteLine("Lighting the oven's gas!");
            this.On = true;
        }

        public void ExtinguishGas()
        {
            Console.WriteLine("Extinguishing the oven's gas!");
            this.On = false;
        }

        public void Bake(string item)
        {
            if (!this.On)
            {
                Console.WriteLine("Oven's gas is not turned on.");
            }
            else
            {
                Console.WriteLine("Now baking " + item + "!");
            }
        }
    }
}