Product.cs

1234567891011121314151617181920212223242526272829303132using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace HelloCSharp
{
    class Product
    {
        private string name;
        private string thumbnail;
        private int price;
        private int shipCost;
        private string[] materials;
        private string introduce;
        private string description;

        protected int serialNumber;

        public Product()
        {
        }

        public Product(int _s)
        {
            serialNumber = _s;
        }

        public int SerialNumber { get => serialNumber; }
    }
}

Phone.cs

123456789101112131415161718192021222324252627282930313233using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace HelloCSharp
{
    struct Color
    {
        byte r;
        byte g;
        byte b;
    }

    class Phone : Product
    {
        string imei;
        Color color;

        /*
        public Phone(int _s) : base(_s)
        {
        }
        */

        public Phone(int _s)
        {
            serialNumber = _s;
        }
    }
}

Laptop.cs

1234567891011121314using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace HelloCSharp
{
    class Laptop : Product
    {
        public Laptop(int _s) : base(_s)
        {

        }

Program.cs

1234567891011121314151617181920212223242526272829303132333435363738394041424344454647484950515253using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.IO;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;
using Stdio;

namespace HelloCSharp
{
    class Program
    {
        static void Main(string[] args)
        {
            Phone[] phones = new Phone[10];
            Laptop[] laptops = new Laptop[10];

            for (int i = 0; i < phones.Length; i++)
            {
                phones[i] = new Phone(0 + i);
            }

            for (int i = 0; i < laptops.Length; i++)
            {
                laptops[i] = new Laptop(100 + i);
            }

            int productSerialNumber = 3;

            for (int i = 0; i < phones.Length; i++)
            {
                if (productSerialNumber == phones[i].SerialNumber)
                {

                }
            }

            for (int i = 0; i < laptops.Length; i++)
            {
                if (productSerialNumber == laptops[i].SerialNumber)
                {

                }
            }


            Console.ReadLine();
        }
    }
}