大学课设项目，Windows端基于UDP的网络聊天程序的服务端和客户端

前言

本次项目可以作为之前内容的一个扩展，学会在Windows端进行网络通信。
该项目需要用到的知识手段较多，在编写该项目的同时也可以对之前C++方面的知识进行一个不错的回顾。

项目需求介绍

本次项目用到 Windows网络套接字编程，多线程，线程池，线程安全，互斥锁，IO流，文件管理，数据结构设计，序列化，反序列化，自定义协议，STL等相关知识和技术。

提示：以下是本篇文章正文内容，下面案例可供参考

一、服务端

1.对Udp套接字进行一个封装

//Socket.h
#pragma once
#include<iostream>
#include<string>
#include<WinSock2.h>
#include<Windows.h>
#include<thread>
#include<functional>
#pragma comment(lib, "ws2_32.lib") // 链接库文件#pragma warning(disable:4996)      //防止VS发出4996号警告enum Erro
{Sock_Error = 1,Bind_Error,Listen_Error
};
class Socket
{
public:Socket(){}void Init(){_listensock = socket(AF_INET, SOCK_DGRAM, 0);if (_listensock == SOCKET_ERROR){//套接字创建失败std::cout << "Socket Create Error..." << std::endl;exit(Sock_Error);}}void Bind(const std::string& ip, const int port){memset(&_sockaddr, 0, sizeof _sockaddr);_sockaddr.sin_family = AF_INET;_sockaddr.sin_addr.s_addr = inet_addr(ip.c_str());_sockaddr.sin_port = htons(port);int n = bind(_listensock, (const struct sockaddr*)&_sockaddr, sizeof _sockaddr);if (n < 0){std::cout << "Bind Error..." << std::endl;//std::cout << errno << " " << strerror(errno) << std::endl;exit(Bind_Error);}}~Socket(){closesocket(_listensock);}public:SOCKET _listensock;  struct sockaddr_in _sockaddr;
};

Windows OS 和 Linux OS 所提供的网络套接字接口函数有一点点的不同，但是实际的使用差别并不是很大！ 所以这里就不细讲了。

2. UdpServer的编写

// UdpServer.h
class UdpServer
{
public:UdpServer(){_tp = ThreadPool<Task>::GetInstance();_user_map = new std::unordered_map<std::string, std::string>;_online_map = new std::unordered_map<std::string, struct sockaddr_in>;_buffer = new std::unordered_map<std::string, std::string>;_mutex = new std::mutex;}void Init(){//初始化网络环境WSADATA wsd;WSAStartup(MAKEWORD(2, 2), &wsd);_host.Init();_host.Bind(server_ip, server_port);ReadUser();}void ReadUser(){std::ifstream in("User.txt");if (!in.is_open()){//文件打开失败std::cout << "Open FIle Error..." << std::endl;}std::string line;while (std::getline(in, line)){//"username passwd\n"size_t pos = line.find(' ');std::string username = line.substr(0, pos);std::string passwd = line.substr(pos + 1);_user_map->insert(std::pair<std::string,std::string>(username,passwd));}std::cout << "--------------------------------------------------------------" << std::endl;std::cout << "所有已注册账号密码" << std::endl;for (auto& e : *_user_map){std::cout << e.first << " " << e.second << std::endl;}std::cout << "--------------------------------------------------------------" << std::endl;}void Start(){_tp->Start();struct sockaddr_in client;char inbuffer[1024];std::string recvmes;while (true){int len = sizeof client; // unsigned intmemset(&client, 0, sizeof client);// 服务器接受数据//std::cout << "开始等待数据" << std::endl;int n = recvfrom(_host._listensock, inbuffer, sizeof inbuffer - 1, 0, (sockaddr*)&client, &len);if (n > 0){inbuffer[n] = '\0';recvmes = inbuffer;while (!recvmes.empty()){Request rq;if (!rq.deserialize(recvmes)){//报文错误，丢弃所有报文std::cout << "报文错误" << std::endl;break;}Task task(rq, client,_user_map,_mutex,_host._listensock,_online_map,_buffer);_tp->Push(task);}}else{std::cout << "Read Error..." << std::endl;exit(1);}}}~UdpServer(){WSACleanup();   //清理网络环境}
private:Socket _host;ThreadPool<Task>* _tp;std::unordered_map<std::string, std::string>* _user_map;std::unordered_map<std::string, struct sockaddr_in>* _online_map;std::unordered_map<std::string, std::string>* _buffer;std::mutex* _mutex;
};

我们也对UdpServer也进行了一个封装，这里如果想要的话还可以继续接着完善，加入守护线程和单例模式，大家感兴趣可以下来试一试。

主线程老老实实打印数据，其他线程就去处理客户端发来的命令。

我们可以看到类里面有许多成员变量， 这里对这些变量都进行解释一下。

Socket _host; 毫无疑问，服务端必须要申请一个套接字
ThreadPool* _tp; 这个是线程池的实例指针
std::unordered_map<std::string, std::string>* _user_map; 这个是服务器维护所有注册用户的哈希map
std::unordered_map<std::string, struct sockaddr_in>* _online_map; 这个是服务器维护所有在线用户的哈希map
std::unordered_map<std::string, std::string>* _buffer; 这个是存放所有注册用户离线消息的缓冲区
std::mutex* _mutex; 这个是为了保证线程安全提供的互斥锁

既然服务器想要维护所有用户信息，那么文件管理的IO就必不可少，所以这里也提供了 ReadUser函数

    void ReadUser(){std::ifstream in("User.txt");if (!in.is_open()){//文件打开失败std::cout << "Open FIle Error..." << std::endl;}std::string line;while (std::getline(in, line)){//"username passwd\n"size_t pos = line.find(' ');std::string username = line.substr(0, pos);std::string passwd = line.substr(pos + 1);_user_map->insert(std::pair<std::string,std::string>(username,passwd));}std::cout << "--------------------------------------------------------------" << std::endl;std::cout << "所有已注册账号密码" << std::endl;for (auto& e : *_user_map){std::cout << e.first << " " << e.second << std::endl;}std::cout << "--------------------------------------------------------------" << std::endl;}

作为初始化_user_map的函数。

3. Task.h

//Task.h
#pragma once#include<iostream>
#include<string>
#include<unordered_map>
#include<mutex>
#include<fstream>#include"protocol.h"
#include"Socket.h"std::string offline_message =
"-------------------------------------------------------------------------------\n\离线消息\n";enum Code {Login_Err = -1,Normal = 0,Online_User,All_User
};
class Task
{
public:Task(){}Task(const Request& rq, struct sockaddr_in client, std::unordered_map<std::string, std::string>* user_map ,std::mutex* mutex, SOCKET host, std::unordered_map<std::string, struct sockaddr_in>* online_map,std::unordered_map<std::string, std::string>* buffer):_rq(rq), _client(client),_user_map(user_map),_mutex(mutex) ,_host(host),_online_map(online_map),_buffer(buffer) {}void SendOneMessage(int code, const std::string& info, const struct sockaddr_in client){Respond rs(info, code);std::string mes;rs.serialize(&mes);sendto(_host, mes.c_str(), mes.size(), 0, (const struct sockaddr*)(&client), sizeof client);}void SendEveryoneMessage(const std::string& info){Respond rs(info);std::string mes;rs.serialize(&mes);for (auto& user : *_online_map){sendto(_host, mes.c_str(), mes.size(), 0, (const struct sockaddr*)&(user.second), sizeof(user.second));}}bool CheckUser(const std::string& name, const std::string& mes){auto a_it = _user_map->find(name);if (a_it == _user_map->end()){//不存在该用户SendOneMessage(Login_Err, std::string("该用户未注册，请输入/quit退出聊天框"), _client);return false;}auto o_it = _online_map->find(name);if (o_it == _online_map->end()){//该用户不在线SendOneMessage(0, std::string("该用户未上线，您可以继续发送离线消息，对方在上线后可查看"), _client);Respond rs(mes,0);std::string tmp;rs.serialize(&tmp);_mutex->lock();(*_buffer)[name] += tmp;_mutex->unlock();return false;}return true;}void SendSpecifiedUser(const std::string& client_name, const std::string& name, const std::string& info){std::string mes = "<";mes += client_name;mes += ">: ";mes += info;if (!CheckUser(name,mes)){return;}struct sockaddr_in spc_user = (*_online_map)[name];SendOneMessage(0, mes, spc_user);}void GetOnlineUser(std::string* out){std::string tmp;for (auto& e : *_online_map){tmp += e.first;tmp += '\n';}*out = tmp;}void GetAllUser(std::string* out){std::string tmp;for (auto& e : *_user_map){tmp += e.first;tmp += '\n';}*out = tmp;}void WriteUser(const std::string& name, const std::string& passwd){std::ofstream file("User.txt", std::ios::app);if (file){file << name << " " << passwd << std::endl;file.close();}else{std::cout << "写入失败" << std::endl;}}bool UserRegisterCheck(std::string& name, std::string& passwd){auto it = _user_map->find(name);if (it == _user_map->end()){//没找到,可以进行注册_mutex->lock();(*_user_map)[name] = passwd;_mutex->unlock();WriteUser(name, passwd);std::string mes = "Sign Up Succeed!";SendOneMessage(0, mes,_client);mes = "用户<";mes += name;mes += "> 已上线,快来找他聊天吧";SendEveryoneMessage(mes);_mutex->lock();(*_online_map)[name] = _client;_mutex->unlock();return true;}else{std::string mes = "Sign Up Failed, The Same UserName Already Exists";SendOneMessage(Login_Err, mes, _client);return false;}}bool UserLoginCheck(std::string& name, std::string& passwd){std::string mes;auto it = _user_map->find(name);if (it == _user_map->end()){//没找到直接Passmes = "Sign In Failed, Your Account Is Wrong";SendOneMessage(Login_Err, mes, _client);return false;}if ((*_user_map)[name] != passwd){//密码错误mes = "Sign In Failed, Your Password Is Wrong";SendOneMessage(Login_Err, mes, _client);return false;}if (_online_map->find(name) != _online_map->end()){//当前用户已经在线了mes = "The User has Signed In";SendOneMessage(Login_Err, mes, _client);return false;}mes = "Sign In Succeed! Weclome Back ";mes += name;mes += "!";SendOneMessage(0, mes, _client);mes = "用户<";mes += name;mes += "> 已上线,快来找他聊天吧";SendEveryoneMessage(mes);_mutex->lock();(*_online_map)[name] = _client;_mutex->unlock();//发送离线消息if (_buffer->find(name) != _buffer->end()){//离线buffer有它的信息SendOneMessage(Normal, offline_message, _client);sendto(_host, (*_buffer)[name].c_str(), (*_buffer)[name].size(), 0, (const struct sockaddr*)(&_client), sizeof _client);_mutex->lock();_buffer->erase(name);_mutex->unlock();}return true;}void LogOut(const std::string& name){auto o_it = _online_map->find(name);if (o_it == _online_map->end()){//该用户不在线return;}_mutex->lock();_online_map->erase(name);_mutex->unlock();std::string mes;mes = "用户<";mes += name;mes += "> 已下线";SendEveryoneMessage(mes);}void run(){//根据类型处理信息if (_rq._type == "/signup"){//注册流程UserRegisterCheck(_rq._info1, _rq._info2);}else if (_rq._type == "/signin"){//登录流程UserLoginCheck(_rq._info1, _rq._info2);}else if (_rq._type == "/getonline"){//给客户端发在线用户表std::string online;GetOnlineUser(&online);SendOneMessage(Online_User, online, _client);}else if (_rq._type == "/getall"){std::string all;GetAllUser(&all);SendOneMessage(All_User, all, _client);}else if (_rq._type == "/exit"){//下线LogOut(_rq._info1);}else if (_rq._type.find("/info") != std::string::npos){std::string client_name = _rq._type.substr(5);SendSpecifiedUser(client_name,_rq._info1, _rq._info2);}}void operator()(){run();}~Task(){}private:Request _rq;struct sockaddr_in _client;std::unordered_map<std::string, std::string>* _user_map;std::unordered_map<std::string, struct sockaddr_in>* _online_map;std::unordered_map<std::string, std::string>* _buffer;std::mutex* _mutex;SOCKET _host;};

Task.h其实才是重中之重，所有服务器的需求我都写在了这里面，可以根据函数名和成员变量来分析每个函数都是实现了一个怎样的功能。 该项目服务器所有功能的实现，我都进行了接近完美的封装。

4.protocol.h的编写

#pragma once#include <iostream>
#include <string>const char blank_space_sep = ' ';
const char protocol_sep = '&';class Request
{
public:Request() {} // 提供一个无参构造Request(const std::string& type, const std::string& info1 = "", const std::string& info2 = ""): _type(type), _info1(info1), _info2(info2) {}Request(const char* type, const  char* info1, const  char* info2): _type(type), _info1(info1), _info2(info2) {}bool serialize(std::string* out_str){// 协议规定 字符串格式应序列化为"len\n_type _info1 _info2\n"std::string main_body = _type;main_body += blank_space_sep;main_body += _info1;main_body += blank_space_sep;main_body += _info2;*out_str = std::to_string(main_body.size());*out_str += protocol_sep;*out_str += main_body;*out_str += protocol_sep;return true;}bool deserialize(std::string& in_str){// 协议规定 in_str的格式应为"len&_type _info1 _info2&"size_t pos = in_str.find(protocol_sep);if (pos == std::string::npos){// 说明没找到'&'return false;}std::string sl = in_str.substr(0, pos);int len = std::stoi(sl); // 如果这里的sl不是一串数字，stoi就会抛异常！ BUG?  严格限制客户端行为！size_t total_len = sl.size() + 1 + len + 1;if (in_str.size() < total_len){return false;}if (in_str[total_len - 1] != protocol_sep){return false;}std::string main_body = in_str.substr(pos + 1, len);// main_body"_type _info1 _info2"size_t left = main_body.find(blank_space_sep);if (left == std::string::npos){// 说明没找到' 'return false;}size_t right = main_body.rfind(blank_space_sep);if (left == right){// 说明只有一个' 'return false;}_type = main_body.substr(0, left);   _info2 = main_body.substr(right + 1);_info1 = main_body.substr(left + 1, right - left - 1);in_str.erase(0, total_len);return true;}void print(){std::cout << _type << " " << _info1 << " " << _info2 << std::endl;}~Request() {}public:std::string _type;std::string _info1;std::string _info2;
};class Respond
{
public:Respond() {} // 提供一个无参构造Respond(std::string info, int code = 0): _info(info), _code(code) {}bool serialize(std::string* out_str){// 协议规定 字符串格式应序列化为"len&_code _info"std::string main_body = std::to_string(_code);main_body += blank_space_sep;main_body += _info;*out_str = std::to_string(main_body.size());*out_str += protocol_sep;*out_str += main_body;*out_str += protocol_sep;return true;}bool deserialize(std::string& in_str){// 协议规定 in_str的格式应为"len&_code _info"size_t pos = in_str.find(protocol_sep);if (pos == std::string::npos){// 说明没找到'&'return false;}std::string sl = in_str.substr(0, pos);int len = std::stoi(sl); // 如果这里的sl不是一串数字，stoi就会抛异常！ BUG?  严格限制客户端行为！size_t total_len = sl.size() + 1 + len + 1;if (in_str.size() < total_len){return false;}if (in_str[total_len - 1] != protocol_sep){return false;}std::string main_body = in_str.substr(pos + 1, len);// main_body"_code _info"size_t blank = main_body.find(blank_space_sep);if (blank == std::string::npos){// 说明没找到' 'return false;}_code = std::stoi(main_body.substr(0, blank));_info = main_body.substr(blank + 1);in_str.erase(0, total_len);return true;}void print(){std::cout << _code << " " << _info << std::endl;}~Respond() {}public:int _code; // 表示结果可信度  0表示可信std::string _info;
};

序列化和反序列化，我们之前也有写过。 因为我们这里服务器跟客户端的需求过多，所以就需要对提交来的数据进行分析。
class Request
{
_type 作为客户端想要执行的命令
_info1 作为客户端发来的信息1
_info 2 作为客户端发来的信息2
}

class Respond{
_code 作为服务端向客户端数据的标识符（解释）
_info 作为服务端向客户端发送的信息
}

5.线程池的编写

#pragma once#include<iostream>
#include<thread>
#include<string>
#include<mutex>
#include<vector>
#include<queue>
#include<condition_variable>static const int defalutnum = 10;template <class T>
class ThreadPool
{
public:void Wakeup(){_cond.notify_one();}void ThreadSleep(std::unique_lock<std::mutex>& lock){_cond.wait(lock);}bool IsQueueEmpty(){return _tasks.empty();}public:static void HandlerTask(ThreadPool<T>* tp){while (true){T t;{std::unique_lock<std::mutex>lock(_mutex);while (tp->IsQueueEmpty()){tp->ThreadSleep(lock);}t = tp->Pop();}t();}}void Start(){size_t num = _threads.size();for (int i = 0; i < num; i++){_threads[i] = std::thread(HandlerTask, this);}}T Pop(){T t = _tasks.front();_tasks.pop();return t;}void Push(const T& t){std::unique_lock<std::mutex>lock(_mutex);_tasks.push(t);Wakeup();}static ThreadPool<T>* GetInstance(){if (nullptr == _tp) {std::unique_lock<std::mutex>lock(_lock);if (nullptr == _tp){_tp = new ThreadPool<T>();}}return _tp;}private:ThreadPool(int num = defalutnum) : _threads(num){}~ThreadPool() {}ThreadPool(const ThreadPool<T>&) = delete;const ThreadPool<T>& operator=(const ThreadPool<T>&) = delete;
private:std::vector<std::thread> _threads;std::queue<T> _tasks;static std::mutex _mutex;std::condition_variable _cond;static ThreadPool<T>* _tp;static std::mutex _lock;
};template <class T>
ThreadPool<T>* ThreadPool<T>::_tp = nullptr;template <class T>
std::mutex ThreadPool<T>::_lock;template <class T>
std::mutex ThreadPool<T>::_mutex;

这里的线程池，我直接采用了C++11提供的Thread类，并进行了完美的封装。

6.main.cc

这个我是不太想贴出来的，有点侮辱大家的智商，不过考虑到广大大学生…

#include"UdpServer.h"int main()
{UdpServer us;us.Init();us.Start();return 0;
}

二、客户端

1. Socket.h

与服务端Socket.h代码一致

2.protocol.h

与服务端protocol.h代码一致

3.UdpClient

#pragma once#include<string>
#include<thread>#include"protocol.h"
#include"Socket.h"
#include"menu.h"
#pragma comment(lib, "ws2_32.lib") // 链接库文件
#pragma warning(disable:4996)      //防止VS发出4996号警告const int server_port = 8080;
const std::string server_ip = "127.0.0.1"; //提前写好服务器IPstd::string yourname = "";enum Code {Login_Err = -1,Normal = 0,Online_User,All_User
};struct Thread_Data
{SOCKET socket_fd;struct sockaddr_in server;
};void GetOnlineUser(const Thread_Data& data)
{Request rq("/getonline");std::string info;rq.serialize(&info);sendto(data.socket_fd, info.c_str(), (int)info.size(), 0, (const struct sockaddr*)&data.server, sizeof(data.server));
}void GetAllUser(const Thread_Data& data)
{Request rq("/getall");std::string info;rq.serialize(&info);sendto(data.socket_fd, info.c_str(), (int)info.size(), 0, (const struct sockaddr*)&data.server, sizeof(data.server));
}void Exit(const Thread_Data& data)
{Request rq("/exit", yourname);std::string info;rq.serialize(&info);sendto(data.socket_fd, info.c_str(), (int)info.size(), 0, (const struct sockaddr*)&data.server, sizeof(data.server));exit(0);
}void recv_mes(const Thread_Data& data)
{char buffer[1024];std::string message;while (true){memset(buffer, 0, sizeof(buffer));struct sockaddr_in tmp;int tmp_len = sizeof(tmp);int n = recvfrom(data.socket_fd, buffer, sizeof(buffer) - 1, 0, (struct sockaddr*)&tmp, &tmp_len);if (n > 0){buffer[n] = 0;message = buffer;while (!message.empty()){Respond rs;if (!rs.deserialize(message)){//报文错误，丢弃所有报文std::cout << "报文错误" << std::endl;break;}if (rs._code == Online_User){PrintOnline(rs._info);continue;}else if (rs._code == All_User){PrintAll(rs._info);continue;}std::cout << rs._info << std::endl;}}else{std::cout << "Recv Error..." << std::endl;exit(1);}}
}void LoginPage(const Thread_Data& data)
{std::string name;while (true){std::cout << sign_page << std::endl;std::string login;std::cin >> login;std::string passwd;if (login == "1"){//登录std::cout << "请输入你的账号@";std::cin >> name;std::cout << "请输入你的密码@";std::cin >> passwd;Request rq("/signin", name.c_str(), passwd.c_str());std::string mes;rq.serialize(&mes);sendto(data.socket_fd, mes.c_str(), (int)mes.size(), 0, (const struct sockaddr*)&data.server, sizeof(data.server));break;}else if (login == "2"){//注册while (true){std::cout << "请输入你要注册的账号@";std::cin >> name;std::cout << "请输入你要注册的密码@";std::cin >> passwd;std::string confirm;std::cout << "请重新输入你的密码@";std::cin >> confirm;if (confirm != passwd){std::cout << "两次输入的密码不正确，请重新注册" << std::endl;continue;}break;}Request rq("/signup", name.c_str(), passwd.c_str());std::string mes;rq.serialize(&mes);sendto(data.socket_fd, mes.c_str(), (int)mes.size(), 0, (const struct sockaddr*)&data.server, sizeof(data.server));break;}else{//用户输入错误std::cout << "输入错误，请重新输入" << std::endl;continue;}}yourname = name;
}void HandRequest(const Thread_Data& data)
{std::string message;std::cout << ico << std::endl;while (true){LoginPage(data);//回应请求char buffer[1024];memset(buffer, 0, sizeof(buffer));struct sockaddr_in tmp;int tmp_len = sizeof tmp;int n = recvfrom(data.socket_fd, buffer, sizeof(buffer) - 1, 0, (struct sockaddr*)&tmp, &tmp_len);if (n > 0){buffer[n] = 0;message = buffer;Respond rs;rs.deserialize(message);std::cout << rs._info << std::endl;if (rs._code == Login_Err){std::cout << "请重新登录/注册" << std::endl;continue;}break;}else{std::cout << "Hand Recv Error..." << std::endl;exit(1);}}}void ConnectUser(const Thread_Data& data, const std::string& name)
{std::string mes;std::cout << "------------------------------------------------------------------------------------------" << std::endl;std::cout << "                                          聊天框" << std::endl;std::cout << "小帮手： 想要退出聊天框请输入/quit" << std::endl;while (true){std::cout << "Send A Message@";std::cin >> mes;if (mes == "/help"){HelpMenu();continue;}else if (mes == "/quit"){break;}else if (mes == "/online"){GetOnlineUser(data);continue;}else if (mes == "/all"){GetAllUser(data);continue;}else if (mes == "/clear"){system("cls");}else if (mes == "/exit"){Exit(data);}std::string cmd = "/info";cmd += yourname;Request rq(cmd.c_str(), name, mes.c_str());std::string info;rq.serialize(&info);sendto(data.socket_fd, info.c_str(), (int)info.size(), 0, (const struct sockaddr*)&data.server, sizeof(data.server));std::cout << "成功发送消息" << std::endl;}std::cout << "------------------------------------------------------------------------------------------" << std::endl;
}void send_mes(const Thread_Data& data)
{HelpMenu();std::string command;std::string name;while (true){std::cin >> command;//根据if(command == "/online"){ GetOnlineUser(data);continue;}else if (command == "/all"){GetAllUser(data);continue;}else if (command == "/help"){HelpMenu();continue;}else if (command == "/go"){GetOnlineUser(data);std::cout << "你想要和谁聊天？" << std::endl;std::cin >> name;if (name == yourname){std::cout << "不可与自己聊天，退出" << std::endl;continue;}ConnectUser(data, name);std::cout << "你已离开与 " << name << " 的聊天，" << "可以输入/online ，查看当前在线用户" << std::endl;}else if (command == "/clear"){system("cls");}else if (command == "/exit"){Exit(data);}else{std::cout << "未知命令，输入/help来查看所有命令" << std::endl;}}
}class UdpClient {
public:UdpClient() {}void Init(){WSADATA wsd;WSAStartup(MAKEWORD(2, 2), &wsd);_host.Init();}void Start(){struct sockaddr_in server;memset(&server, 0, sizeof server);server.sin_family = AF_INET;server.sin_addr.s_addr = inet_addr(server_ip.c_str());server.sin_port = htons(server_port);std::thread threads[2];Thread_Data data;data.server = server;data.socket_fd = _host._listensock;//等待第一次握手请求HandRequest(data);threads[1] = std::thread(send_mes, std::ref(data));threads[0] = std::thread(recv_mes, std::ref(data));threads[0].join();threads[1].join();}~UdpClient() {WSACleanup();   //清理网络环境}
private:Socket _host;
};

客户端的设计，我是分为两个部分，第一个部分我称为客户端的握手请求，
让客户端进行登录或注册。 然后再进入第二个部分，从这里开始读取数据和写数据就使用多线程让两个模块进行分离。

写数据的进程 可以让用户自由选择交互命令，读数据的进程分析服务器发来的数据，并进行响应。

4.menu.h

#pragma once#include<string>
#include<iostream>
#include<vector>
//#pragma execution_character_set("utf-8")const std::string ico =
"  ______                      _                 _   _        _____ _           _  \n\|  ____|                    | |               (_) ( )      / ____| |         | | \n\| |__ ___ _ __   __ _       | |_   _ _ __  _____  |/ ___  | |    | |__   __ _| |_ \n\|  __/ _ \\ '_ \\ / _` |  _   | | | | | '_ \\|_  / |   / __| | |    | '_ \\ / _` | __|\n\| | |  __/ | | | (_| | | |__| | |_| | | | |/ /| |   \\__ \\ | |____| | | | (_| | |_ \n\|_|  \\___|_| |_|\\__, |  \\____/ \\__,_|_| |_/___|_|   |___/  \\_____|_| |_|\\__,_|\\__|\n\__/ |                                                            \n\|___/                                                             \n";const std::string sign_page =
" ------------------------------------------------------------------------------------------\n\
|           1.sign in(登录)                                2. sign up(注册)               |\n\
|                                       请输入序号                                        |\n\
|                                                                                         |\n\------------------------------------------------------------------------------------------";const std::vector<std::string> OKword = { "" };void PrintOnline(const std::string& online)
{std::cout << "------------------------------------------------------------------------------------------" << std::endl;std::cout << "                                        当前在线用户" << std::endl;std::cout << online << std::endl;std::cout << "------------------------------------------------------------------------------------------" << std::endl;
}void PrintAll(const std::string& all)
{{std::cout << "------------------------------------------------------------------------------------------" << std::endl;std::cout << "                                        所有注册用户" << std::endl;std::cout << all << std::endl;std::cout << "------------------------------------------------------------------------------------------" << std::endl;}}void HelpMenu()
{printf(" --------------------------------------------------------------------------------------------------------------------\n\
|                                                  小帮手                                                            |\n\
| 输入/online  可以查看当前在线用户                                                                                  |\n\
| 输入/all     可以查看所有注册用户                                                                                  |\n\
| 输入/help    可以再次召唤小帮手                                                                                    |\n\
| 输入/go      进入一个指定用户的聊天窗口，在聊天窗口内不可使用/go命令，期间可以收到其他用户发来的消息               |\n\
| 输入/quit    可以离开与当前用户的聊天窗口                                                                          |\n\
| 输入/clear   可以清理界面                                                                                          |\n\
| 输入/exit    关闭客户端，下线                                                                                      |\n\
|                                                                                                                    |\n\
| WARNING: 由于该程序采用UDP协议，为无连接传输协议，请登录后务必使用/exit退出程序，不要直接关闭客户端，否则后果自负  |\n\
| WARNING: 由于该程序采用UDP协议，为无连接传输协议，请登录后务必使用/exit退出程序，不要直接关闭客户端，否则后果自负  |\n\
| WARNING: 由于该程序采用UDP协议，为无连接传输协议，请登录后务必使用/exit退出程序，不要直接关闭客户端，否则后果自负  |\n\--------------------------------------------------------------------------------------------------------------------\n");
}

这个头文件就主要是在命令行界面一定程度上做一些仿图形界面，方便美观。

5.main.cpp

#include"UdpClient.h"int main()
{UdpClient uc;uc.Init();uc.Start();return 0;
}

三、运行图

这里我就不放出服务器运行的图片了，因为服务器运行的时候，我没有写什么输出屏幕语句，所以啥也没有。