# 修改默认程序

现在src目录有三个独立的目录，每个都包含main.mo模板文件。本章节中，你需要用不同的actor替换每个main.mo文件。‌

修改源码步骤如下‌

1. 打开src/assistant/main.mo文件并删除已有内容
2. 复制粘贴下面的代码

   ```
   import Array "mo:base/Array";
   import Nat "mo:base/Nat";

   // Define the actor
   actor Assistant {

     stable var todos : [ToDo] = [];
     stable var nextId : Nat = 1;

     // Define to-do item properties
     type ToDo = {
       id : Nat;
       description : Text;
       completed : Bool;
     };

     // Add to-do item utility
     func add(todos : [ToDo], description : Text, id : Nat) : [ToDo] {
       let todo : ToDo = {
         id = id;
         description = description;
         completed = false;
       };
       Array.append(todos, [todo])
   };

     // Show to-do item utility
     func show(todos : [ToDo]) : Text {
       var output : Text = "\n___TO-DOs___";
       for (todo : ToDo in todos.vals()) {
         output #= "\n(" # Nat.toText(todo.id) # ") " # todo.description;
         if (todo.completed) { output #= " ✔"; };
       };
       output
     };

     public func addTodo (description : Text) : async () {
       todos := add(todos, description, nextId);
       nextId += 1;
     };

     public query func showTodos () : async Text {
       show(todos)
     };

   };
   ```
3. 保存并关闭main.mo文件
4. 打开src/rock\_paper\_scissors/main.mo文件并删除已有内容
5. 复制粘贴下面的代码

   ```
   import I "mo:base/Iter";

   actor RockPaperScissors {

     stable var alice_score : Nat = 0;
     stable var bob_score : Nat = 0;
     stable var alice_last : Choice = #scissors;
     stable var bob_last : Choice = #rock;

     type Choice = {
       #rock;
       #paper;
       #scissors;
     };

     public func contest() : async Text {
       for (i in I.range(0, 99)) {
         battle_round();
       };
       var winner = "The contest was a draw";
       if (alice_score > bob_score) winner := "Alice won"
       else if (alice_score < bob_score) winner := "Bob won";
       return (winner);
     };

     func battle_round() : () {
       let a = alice(bob_last);
       let b = bob(alice_last);

       switch (a, b) {
         case (#rock, #scissors) alice_score += 1;
         case (#rock, #paper) bob_score += 1;
         case (#paper, #scissors) alice_score += 1;
         case (#paper, #rock) bob_score += 1;
         case (#scissors, #paper) alice_score += 1;
         case (#scissors, #rock) bob_score += 1;
         case (#rock, #rock) alice_score += 0;
         case (#paper, #paper) bob_score += 0;
         case (#scissors, #scissors) alice_score += 0;
       };

       alice_last := a;
       bob_last := b;

       return ();
     };

     // Hard-coded players and choices
     func bob(last : Choice) : Choice {
       return #paper;
     };

     func alice(last : Choice) : Choice {
       return #rock;
     };
   };
   ```
6. 保存并关闭main.mo文件
7. 打开src/daemon/main.mo文件并删除已有内容
8. 复制粘贴下面的代码

   ```
   actor Daemon {
     stable var running = false;

     public func launch() : async Text {
       running := true;
       debug_show "The daemon process is running";
     };

     public func stop(): async Text {
       running := false;
       debug_show "The daemon is stopped";
     };
   };
   ```
9. 保存并关闭main.mo文件