异步与多线程_王博阳_无41

homework.cs

@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Threading;
 using System.Threading.Tasks;
@@ -32,6 +32,24 @@ public async Task UpdateInventoryAsync(string title, int quantity)
 
         // TODO: 使用 lock 语句保证线程安全
         // 提示：在 lock 块中查找书籍并更新库存，若库存不足则输出提示
+        lock(_lock)
+        {
+            Book book = _books.Find(bk => bk.Title == title);
+            if (book == null)
+            {
+                Console.WriteLine($"错误：未找到书籍《{title}》。");
+                return;
+            }
+            if (book.Inventory >= quantity)
+            {
+                book.Inventory -= quantity;
+                Console.WriteLine($"成功购买《{title}》{quantity}册，购买后库存：{book.Inventory}。");
+            }
+            else
+            {
+                Console.WriteLine($"购买失败《{title}》{quantity}册，库存不足！当前库存：{book.Inventory}。");
+            }
+        }
     }
 }
 
@@ -42,6 +60,7 @@ public class BookStore
     // TODO: 实现异步购书方法CheckoutAsync，调用 UpdateInventoryAsync
     public async Task CheckoutAsync(string bookTitle, int quantity)
     {
+        await _db.UpdateInventoryAsync(bookTitle, quantity);
     }
 
     public async Task SimulateMultipleUsers()
@@ -59,9 +78,13 @@ public async Task SimulateMultipleUsers()
         // 提示：创建多个 Task 调用 CheckoutAsync，并传入不同书名和数量
         var tasks = new List<Task>
         {
-
+            CheckoutAsync("C#入门", 2),
+            CheckoutAsync("C#入门", 3),
+            CheckoutAsync("异步编程", 1),
+            CheckoutAsync("异步编程", 2),
+            CheckoutAsync("异步编程", 3)
         };
-
+        await Task.WhenAll(tasks);
 
         Console.WriteLine("\n购买后库存：");
         books = await _db.GetBooksAsync();