diff --git a/ChatClient.java b/ChatClient.java
index 8957221..2428be2 100644
--- a/ChatClient.java
+++ b/ChatClient.java
@@ -1,24 +1,29 @@
 import java.net.*;
 import java.io.*;
+import java.util.Scanner;
 
 public class ChatClient {
 
 	public static void main(String[] args) {
-		if(args.length != 2){
-			System.out.println("Usage : java ChatClient <username> <server-ip>");
-			System.exit(1);
-		}
+
+		//#1
+		Scanner input = new Scanner(System.in);
+		System.out.print("your name >> ");
+		String name = input.next();
+		System.out.print("server ip >> ");
+		String ip = input.next();
+
 		Socket sock = null;
 		BufferedReader br = null;
 		PrintWriter pw = null;
 		boolean endflag = false;
 		try{
-			sock = new Socket(args[1], 10001);
+			sock = new Socket(ip, 10001);
 			pw = new PrintWriter(new OutputStreamWriter(sock.getOutputStream()));
 			br = new BufferedReader(new InputStreamReader(sock.getInputStream()));
 			BufferedReader keyboard = new BufferedReader(new InputStreamReader(System.in));
 			// send username.
-			pw.println(args[0]);
+			pw.println(name);
 			pw.flush();
 			InputThread it = new InputThread(sock, br);
 			it.start();
@@ -26,6 +31,8 @@ public static void main(String[] args) {
 			while((line = keyboard.readLine()) != null){
 				pw.println(line);
 				pw.flush();
+				if(line.equals("/userlist"))
+					send_userlist();
 				if(line.equals("/quit")){
 					endflag = true;
 					break;
@@ -50,6 +57,11 @@ public static void main(String[] args) {
 			}catch(Exception ex){}
 		} // finally
 	} // main
+
+	public void send_userlist(){
+
+	}
+
 } // class
 
 class InputThread extends Thread{
diff --git a/ChatServer.java b/ChatServer.java
index 1955d67..8487c96 100644
--- a/ChatServer.java
+++ b/ChatServer.java
@@ -1,4 +1,5 @@
 import java.net.*;
+import java.text.SimpleDateFormat;
 import java.io.*;
 import java.util.*;
 
@@ -6,18 +7,19 @@ public class ChatServer {
 
 	public static void main(String[] args) {
 		try{
-			ServerSocket server = new ServerSocket(10001);
-			System.out.println("Waiting connection...");
-			HashMap hm = new HashMap();
+			ServerSocket server = new ServerSocket(10001); //port번호 10001로 새로운 ServerSocket을 만든다
+			System.out.println("Waiting connection..."); // Waiting connection...이라는 메세지를 터미널에 출력
+			HashMap hm = new HashMap(); //새 해쉬맵을 만듦
 			while(true){
-				Socket sock = server.accept();
-				ChatThread chatthread = new ChatThread(sock, hm);
-				chatthread.start();
+				Socket sock = server.accept(); // sock라는 소켓은 server라는 서버소켓의 요청을 받아들인다.
+				ChatThread chatthread = new ChatThread(sock, hm); // 새로운 ChatThread Object를 만든다.
+				chatthread.start(); 
 			} // while
 		}catch(Exception e){
 			System.out.println(e);
 		}
 	} // main
+	
 }
 
 class ChatThread extends Thread{
@@ -26,15 +28,17 @@ class ChatThread extends Thread{
 	private BufferedReader br;
 	private HashMap hm;
 	private boolean initFlag = false;
+
+
 	public ChatThread(Socket sock, HashMap hm){
 		this.sock = sock;
 		this.hm = hm;
 		try{
-			PrintWriter pw = new PrintWriter(new OutputStreamWriter(sock.getOutputStream()));
-			br = new BufferedReader(new InputStreamReader(sock.getInputStream()));
-			id = br.readLine();
-			broadcast(id + " entered.");
-			System.out.println("[Server] User (" + id + ") entered.");
+			PrintWriter pw = new PrintWriter(new OutputStreamWriter(sock.getOutputStream())); // sock의 OutputStream으로 PrintWriter를 만듦
+			br = new BufferedReader(new InputStreamReader(sock.getInputStream())); // sock의 InputStream으로 Input Buffer를 만듦
+			id = br.readLine(); //input buffer로 id를 읽음
+			broadcast(id + " entered.");  
+			System.out.println("[Server] User (" + id + ") entered."); //
 			synchronized(hm){
 				hm.put(this.id, pw);
 			}
@@ -43,6 +47,8 @@ public ChatThread(Socket sock, HashMap hm){
 			System.out.println(ex);
 		}
 	} // construcor
+
+
 	public void run(){
 		try{
 			String line = null;
@@ -67,29 +73,42 @@ public void run(){
 			}catch(Exception ex){}
 		}
 	} // run
+
+
 	public void sendmsg(String msg){
 		int start = msg.indexOf(" ") +1;
 		int end = msg.indexOf(" ", start);
 		if(end != -1){
 			String to = msg.substring(start, end);
-			String msg2 = msg.substring(end+1);
+			String msg2 = msg.substring(end + 1);
 			Object obj = hm.get(to);
 			if(obj != null){
-				PrintWriter pw = (PrintWriter)obj;
+				PrintWriter pw = (PrintWriter) obj;
 				pw.println(id + " whisphered. : " + msg2);
 				pw.flush();
 			} // if
 		}
 	} // sendmsg
+
+
 	public void broadcast(String msg){
+		SimpleDateFormat s = new SimpleDateFormat("[a h:mm]");
+		
 		synchronized(hm){
-			Collection collection = hm.values();
-			Iterator iter = collection.iterator();
-			while(iter.hasNext()){
+			Collection collection = hm.values(); //Collection의 값은 HashMap이다.
+			Iterator iter = collection.iterator(); //Iterator 만들기
+			while(iter.hasNext()){	
 				PrintWriter pw = (PrintWriter)iter.next();
-				pw.println(msg);
-				pw.flush();
+
+				//#2
+				pw.println(s.format(System.currentTimeMillis()));
+
+				pw.println(msg); //pw outputStream으로 msg를 전송
+				pw.flush(); // 버퍼 비우기
 			}
 		}
+
 	} // broadcast
+
+
 }