diff --git a/hw1/hw1/Program.cs b/hw1/hw1/Program.cs
index e4f0e15..461dba3 100644
--- a/hw1/hw1/Program.cs
+++ b/hw1/hw1/Program.cs
@@ -2,68 +2,141 @@
 
 namespace Homework1
 {
-    public class Program
-    {
-        public static void Main(string[] args)  // 该程序用于Debug
-        {
-            IProgress progress = new Progress();
-            for (int i = 1; i <= 20; i++)
-            {
-                try
-                {
-                    progress.Start(i*((i%2==0)?1:-1));
-                }
-                catch (Exception e)
-                {
-                    Console.WriteLine(e.Message);
-                }
-                if (i % 3 != 0)
-                {
-                    progress.Add(i-1);
-                }
-                else progress.Sub(i-1);
-
-                if (i == 6 || i == 7)
-                {
-                    progress.Double();
-                }
-                Console.WriteLine(progress.GetProgress().ToString());
-            }
-        }
-    }
-
-    public interface IProgress
-    {
-        public int Num { get; } // Progress的序号，表明是第几个实例化的Progress
-        public int RequiredProgress { get; } // Progress加载完成所需进度
-        public int FinishedProgress { get; } // FinishedProgress指其中已完成的进度, FinishedProgress应当在[0,RequiredProgress]中
-
-        /// <summary>
-        /// 尝试加载下一次进度条，requiredProgress指再次加载进度条所需进度
-        /// 如果之前进度条已经加载完成，则将进度清零开始下一次加载，返回true，但如果requiredProgress<0，应当报错
-        /// 如果之前进度条尚未加载完成，返回false
-        /// </summary>
-        public bool Start(int requiredProgress); 
-        
-        public void Add(int addProgress); //增加addProgress的进度
-        public void Sub(int subProgress); //减少subProgress的进度
-        public void Double(); //进度翻倍
-
-        /// <summary>
-        ///  FinishedProgress指其中已完成的进度，RequiredProgress指当前Progress完成所需进度
-        /// </summary>
-        public (int FinishedProgress, int RequiredProgress) GetProgress();
-    }
-
-    public class Progress : IProgress
-    {
-        // 一个进度条
-        // 只允许修改Progress类中的代码
-        // 要求实现IProgress中的要求
-    }
+public class Program
+{
+public static void Main(string[] args) // 该程序用于Debug
+{
+IProgress progress = new Progress();
+for (int i = 1; i <= 20; i++)
+{
+try
+{
+progress.Start(i*((i%2==0)?1:-1));
+}
+catch (Exception e)
+{
+Console.WriteLine(e.Message);
+}
+if (i % 3 != 0)
+{
+progress.Add(i-1);
+}
+else progress.Sub(i-1);
+
+if (i == 6 || i == 7)
+{
+progress.Double();
+}
+Console.WriteLine(progress.GetProgress().ToString());
+}
+}
+}
+
+public interface IProgress
+{
+public int Num { get; } // Progress的序号，表明是第几个实例化的Progress
+public int RequiredProgress { get; } // Progress加载完成所需进度
+public int FinishedProgress { get; } // FinishedProgress指其中已完成的进度, FinishedProgress应当在[0,RequiredProgress]中
+
+/// <summary>
+/// 尝试加载下一次进度条，requiredProgress指再次加载进度条所需进度
+/// 如果之前进度条已经加载完成，则将进度清零开始下一次加载，返回true，但如果requiredProgress<0，应当报错
+/// 如果之前进度条尚未加载完成，返回false
+/// </summary>
+public bool Start(int requiredProgress); 
+public void Add(int addProgress); //增加addProgress的进度
+public void Sub(int subProgress); //减少subProgress的进度
+public void Double(); //进度翻倍
+
+/// <summary>
+/// FinishedProgress指其中已完成的进度，RequiredProgress指当前Progress完成所需进度
+/// </summary>
+public (int FinishedProgress, int RequiredProgress) GetProgress();
+}
+
+public class Progress : IProgress
+{
+// 一个进度条
+// 只允许修改Progress类中的代码
+// 要求实现IProgress中的要求
+private int num;
+private int requiredProgress = 0;
+private int finishedProgress = 0;
+
+public Progress()
+{
+num = ++Program.instanceCount;
+}
+
+public int Num
+{
+get
+{
+return num;
+}
+}
+
+public int RequiredProgress
+{
+get
+{
+return requiredProgress;
+}
+}
+
+public int FinishedProgress
+{
+get
+{
+return finishedProgress;
+}
+}
+
+public bool Start(int requiredProgress)
+{
+if (requiredProgress < 0)
+throw new ArgumentException("RequiredProgress must be positive.", "Homework1.Progress");
+if (finishedProgress >= this.requiredProgress)
+{
+this.requiredProgress = requiredProgress;
+this.finishedProgress = 0;
+return true;
+}
+else
+{
+return false;
+}
+}
+
+public void Add(int addProgress)
+{
+finishedProgress += addProgress;
+if (finishedProgress > requiredProgress)
+finishedProgress = requiredProgress;
+}
+
+public void Sub(int subProgress)
+{
+finishedProgress -= subProgress;
+if (finishedProgress < 0)
+finishedProgress = 0;
+}
+
+public void Double()
+{
+finishedProgress *= 2;
+if (finishedProgress > requiredProgress)
+finishedProgress = requiredProgress;
+}
+
+public (int FinishedProgress, int RequiredProgress) GetProgress()
+{
+return (FinishedProgress, RequiredProgress);
+}
+}
 
 /*
- * 输出示例：
+* 输出示例：
 RequiredProgress must be positive. (Parameter 'Homework1.Progress')
 (0, 0)
 (1, 2)
@@ -88,5 +161,5 @@ RequiredProgress must be positive. (Parameter 'Homework1.Progress')
 (0, 18)
 (18, 18)
 (19, 20)
- */
+*/
 }
\ No newline at end of file