C++主函数传递对象实现双向收发消息功能异常问题求助

你不需要在sendMsg中创建对象副本，当前传递引用的写法本身是正确的，无法正常显示双向消息是代码逻辑和细节错误导致的，具体问题和修复方案如下：

核心错误点 #

• 遍历方法的循环条件错误：Message::showMsg和Inbox::showRecievedMsg两个方法的for循环终止条件写反了，你用了容器的begin和end比较，而不是迭代器it和end比较，会导致无限循环。
• 打印调用逻辑错误：你调用user2.sendMsg(user1, "Hi")时，这条消息会存入user2的发件箱、user1的收件箱，原代码中调用user2.showRecievedMsg()自然看不到对应内容，应该调用user2.showSendMsg()看user2发出的消息，调用user1.showRecievedMsg()看user1收到的消息。

修复后完整代码 #

#include<bits/stdc++.h>
using namespace std;

class Message{
private:
  list<string> msg;
public:
  void setMsg(string s){
    this->msg.push_front(s);
  }

  list<string> getMsg(){
    return this->msg;
  }

  void showMsg(){
    // 修复循环条件
    for (auto it = this->msg.begin(); it != this->msg.end(); it++)
      cout << *it << endl;
  }
};

class Inbox{
private:
  Message m;
  list<string> r_msg;
public:
  void sendMsg(Inbox &i, string s){
    this->m.setMsg(s);
    i.r_msg.push_front(s);
  }

  void showSendMsg(){
    m.showMsg();
  }

  void showRecievedMsg(){
    // 修复循环条件
    for (auto it = this->r_msg.begin(); it != this->r_msg.end(); it++)
            cout << *it << endl;
  }
};

int main(){
  Inbox user1, user2;
  user1.sendMsg(user2, "hello");
  cout << "===== user1发件箱 =====" << endl;
  user1.showSendMsg();
  cout << "===== user2收件箱 =====" << endl;
  user2.showRecievedMsg();

  user2.sendMsg(user1, "Hi");
  cout << "\n===== user2发件箱 =====" << endl;
  user2.showSendMsg();
  cout << "===== user1收件箱 =====" << endl;
  user1.showRecievedMsg();

  user1.sendMsg(user2, "What are you doing?");
  cout << "\n===== user1发件箱 =====" << endl;
  user1.showSendMsg();
  cout << "===== user2收件箱 =====" << endl;
  user2.showRecievedMsg();

  user2.sendMsg(user1, "Nothing!!");
  cout << "\n===== user2发件箱 =====" << endl;
  user2.showSendMsg();
  cout << "===== user1收件箱 =====" << endl;
  user1.showRecievedMsg();

  user1.sendMsg(user2, "Are you there?");
  cout << "\n===== user1发件箱 =====" << endl;
  user1.showSendMsg();
  cout << "===== user2收件箱 =====" << endl;
  user2.showRecievedMsg();

  user2.sendMsg(user1, "I am lil bit buzy");
  cout << "\n===== user2发件箱 =====" << endl;
  user2.showSendMsg();
  cout << "===== user1收件箱 =====" << endl;
  user1.showRecievedMsg();
  return 0;
}

内容的提问来源于stack exchange，提问作者user9387385