程式碼重構與單元測試——使用“以查詢取代臨時變數”再次對Statement()方法進行重構（七）

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
 
namespace LeasePowerBank
{
 
    /// <summary>
      /// 客戶類
    /// </summary>
   public  class Customer
    {
 
        string Name;//使用者名稱稱
    public    List<Rental> listRentals=new List<Rental>();//使用者租賃的充電寶
        public Customer(string name)
        {
 
           Name = name;
        }
 
        public void AddRental(Rental rental)
        {
 
            listRentals.Add(rental);
        }
 
        public string Statement()
        {
 
            string result = $"{Name} 的租賃賬單：\n";
 
            result += $"總金額為：{GetTotalAmount()}\n";
            result += $"你本次獲得了：{GetTotalFrequentRenterPoints()}積分 ";
            return result;
 
        }
 
        /// <summary>
        /// 計算總金額
        /// </summary>
        private decimal GetTotalAmount()
        {
 
            decimal totalAmount = 0M; //總金額
            foreach (var item in listRentals)
            {
 
                totalAmount+= item.GetAmount();//總價計算            
 
            }
 
            return totalAmount;
 
        }
 
        /// <summary>
        /// 計算積分
        /// </summary>
        private decimal GetTotalFrequentRenterPoints()
        {
            int frequentRenterPoints = 0; //使用者積分
 
            foreach (var item in listRentals)
            {
                frequentRenterPoints += item.GetFrequentRenterPoints();//計算積分
            }
 
            return frequentRenterPoints;
        }
    }
}