CSharp_李果_无48

homework.cs

@@ -31,7 +31,26 @@ public async Task UpdateInventoryAsync(string title, int quantity)
         await Task.Delay(100); // 模拟网络延迟
 
         // 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)
+        {
+            var book = _books.Find(b => b.Title == title);
+            if (book != null)
+            {
+                if (book.Inventory >= quantity)
+                {
+                    book.Inventory -= quantity;
+                    Console.WriteLine($"成功售出 {title} x{quantity}，剩余库存: {book.Inventory}");
+                }
+                else
+                {
+                    Console.WriteLine($"库存不足，无法售出 {title} x{quantity}，当前库存: {book.Inventory}");
+                }
+            }
+            else
+            {
+                Console.WriteLine($"找不到书籍: {title}");
+            }
+        }
     }
 }
 
@@ -42,6 +61,8 @@ public class BookStore
     // TODO: 实现异步购书方法CheckoutAsync，调用 UpdateInventoryAsync
     public async Task CheckoutAsync(string bookTitle, int quantity)
     {
+        Console.WriteLine($"开始处理购买请求: {bookTitle} x{quantity}");
+        await _db.UpdateInventoryAsync(bookTitle, quantity);
     }
 
     public async Task SimulateMultipleUsers()
@@ -56,12 +77,16 @@ public async Task SimulateMultipleUsers()
         Console.WriteLine("\n 开始模拟多用户购书...\n");
 
         // TODO: 使用 Task.WhenAll 模拟多个用户并发购书
-        // 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();