异步&多线程-潘徐成-无26

HW-Async&Thread-1/Program.cs

@@ -56,12 +56,13 @@ public abstract class Expr
 public class ValueExpr(int initVal) : Expr
 {
     int val = initVal;
+    readonly object valLock = new();
     public override int Val
     {
         get
         {
-            // TODO 1:读取操作
-            return val;
+            lock (valLock)
+                return val;
         }
     }
 
@@ -73,18 +74,22 @@ public int NewVal
     {
         set
         {
-            // TODO 2:修改操作
+            lock (valLock)
+                val = value;
+            Update().Wait();
         }
     }
 
     public override async Task Update()
     {
-        // TODO 3:更新操作
+        if (parent != null)
+            await parent.Update();
     }
 
     public override void Register(Expr parent)
     {
-        // TODO 4:注册操作
+        this.parent = parent;
+        Update().Wait();
     }
 }
 
@@ -95,12 +100,13 @@ public override void Register(Expr parent)
 public class AddExpr : Expr
 {
     int val = 0;
+    readonly object valLock = new();
     public override int Val
     {
         get
         {
-            // TODO 5:读取操作
-            return val;
+            lock (valLock)
+                return val;
         }
     }
 
@@ -115,11 +121,15 @@ public AddExpr(Expr A, Expr B)
 
     public override async Task Update()
     {
-        // TODO 6:更新操作
+        lock (valLock)
+            val = ExprA.Val + ExprB.Val;
+        if (parent != null)
+            await parent.Update();
     }
 
     public override void Register(Expr parent)
     {
-        // TODO 7:注册操作
+        this.parent = parent;
+        Update().Wait();
     }
 }

HW-Async&Thread-2/Program.cs

@@ -79,38 +79,58 @@ public class TimeVariable(int initVal = 0, int lowerLimit = 0, int higherLimit =
     int time = Environment.TickCount;
 
     int speed = initSpeed;
+    readonly object speedLock = new();
     /// <summary>
     /// 变化速度，以毫秒计时
     /// </summary>
     public int Speed
     {
         get
         {
-            // TODO 1:保护speed的读取
-            return speed;
+            lock (speedLock)
+                return speed;
         }
         set
         {
-            // TODO 2:请思考speed的改变如何体现在val的变化上？
-            speed = value;
+            lock (speedLock)
+            {
+                lock (valLock)
+                {
+                    var now = Environment.TickCount;
+                    val += (now - time) * Speed;
+                    time = now;
+                    val = val < LowerLimit ? LowerLimit : val > HigherLimit ? HigherLimit : val;
+                }
+                speed = value;
+            }
         }
     }
 
     int val = initVal;
+    readonly object valLock = new();
     /// <summary>
     /// 变量的值
     /// </summary>
     public int Val
     {
         get
         {
-            // TODO 3:直接返回val是否是这个变量当前时刻的值？当然，可以有不同实现
-            return val;
+            lock (valLock)
+            {
+                var now = Environment.TickCount;
+                val += (now - time) * Speed;
+                time = now;
+                val = val < LowerLimit ? LowerLimit : val > HigherLimit ? HigherLimit : val;
+                return val;
+            }
         }
         set
         {
-            // TODO 4:保护val的写入
-            val = value;
+            lock (valLock)
+            {
+                val = value;
+                time = Environment.TickCount;
+            }
         }
     }
 }