Bài số 2 - Part 1

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

namespace ConsoleApplication2
{
    class Program
    {
        static void Main(string[] args)
        {
            int gia_hma = 170000;
            int gia_vip72 = 600000;
            int gia_sockescort = 1000000;
            string ten_kh = "";
            string ten_sanpham = "";
            int sl_sanpham = 0;
            int tongtien = 0;
            int tongtiengiam = 0;
            int tongtienphaitra = 0;
            Console.WriteLine("Bang gia: ");
            Console.WriteLine("HMA: {0} --- Vip72: {1} --- Sockescort: {2} ",gia_hma,gia_vip72,gia_sockescort);
            Console.WriteLine("-----------------------------------------------------------------------------");
            Console.WriteLine("Nhap ten cua ban ? ");
            ten_kh = Console.ReadLine();
            Console.WriteLine("Nhap ten san pham ban muon mua ? ");
            ten_sanpham = Console.ReadLine();
            Console.WriteLine("Nhap vao so luong can mua ? ");
            sl_sanpham = int.Parse(Console.ReadLine());
            if (ten_sanpham == "HMA")
            {
                if (sl_sanpham > 20)
                {
                    tongtien = gia_hma * sl_sanpham;
                    tongtiengiam = (int)(gia_hma * sl_sanpham * 0.3);
                    tongtienphaitra = gia_hma * sl_sanpham - tongtiengiam;
                }

                else if (sl_sanpham > 10 && sl_sanpham < 21)
                {
                    tongtien = gia_hma * sl_sanpham;
                    tongtiengiam = (int)(gia_hma * sl_sanpham * 0.2);
                    tongtienphaitra = gia_hma * sl_sanpham - tongtiengiam;
                }
                else
                {
                    tongtien = gia_hma * sl_sanpham;
                    tongtiengiam = (int)(gia_hma * sl_sanpham * 0.1);
                    tongtienphaitra = gia_hma * sl_sanpham - tongtiengiam;
                }
            }
            else if (ten_sanpham == "Vip72")
            {
                if (sl_sanpham > 20)
                {
                    tongtien = gia_vip72 * sl_sanpham;
                    tongtiengiam = (int)(gia_vip72 * sl_sanpham * 0.3);
                    tongtienphaitra = gia_vip72 * sl_sanpham - tongtiengiam;
                }

                else if (sl_sanpham > 10 && sl_sanpham < 21)
                {
                    tongtien = gia_vip72 * sl_sanpham;
                    tongtiengiam = (int)(gia_vip72 * sl_sanpham * 0.2);
                    tongtienphaitra = gia_vip72 * sl_sanpham - tongtiengiam;
                }
                else
                {
                    tongtien = gia_vip72 * sl_sanpham;
                    tongtiengiam = (int)(gia_vip72 * sl_sanpham * 0.1);
                    tongtienphaitra = gia_vip72 * sl_sanpham - tongtiengiam;
                }
            }
            else if (ten_sanpham == "Sockescort")
            {
                if (sl_sanpham > 20)
                {
                    tongtien = gia_sockescort * sl_sanpham;
                    tongtiengiam = (int)(gia_sockescort * sl_sanpham * 0.3);
                    tongtienphaitra = gia_sockescort * sl_sanpham - tongtiengiam;
                }

                else if (sl_sanpham > 10 && sl_sanpham < 21)
                {
                    tongtien = gia_sockescort * sl_sanpham;
                    tongtiengiam = (int)(gia_sockescort * sl_sanpham * 0.2);
                    tongtienphaitra = gia_sockescort * sl_sanpham - tongtiengiam;
                }
                else
                {
                    tongtien = gia_sockescort * sl_sanpham;
                    tongtiengiam = (int)(gia_sockescort * sl_sanpham * 0.1);
                    tongtienphaitra = gia_sockescort * sl_sanpham - tongtiengiam;
                }
            }
            else
            {
                Console.WriteLine("Nhap sai ten san pham, vui long nhap chinh xac theo ten bang gia, cam on");
                Console.ReadLine();
                return;
            }
            Console.WriteLine("Ten KH: {0} --- Tong tien: {1} --- Tien giam: {2} --- \nTen san pham: {3} --- Tong tien phai tra: {4}",ten_kh,tongtien,tongtiengiam,ten_sanpham,tongtienphaitra);
            if (tongtienphaitra >= 100000 && tongtienphaitra <= 200000)
                Console.WriteLine("Ban duoc +5 point vao tai khoan!");
            else if(tongtienphaitra>=201000 && tongtienphaitra <=400000)
                Console.WriteLine("Ban duoc +10 point vao tai khoan!");
            else if (tongtienphaitra >= 401000 && tongtienphaitra <= 500000)
                Console.WriteLine("Ban duoc +15 point vao tai khoan!");
            else
                Console.WriteLine("Unkown");
            Console.ReadLine();
        }
    }
}