C++ socket编程（TCP）

服务端保持监听客户端， 服务端采用select实现，可以监听多个客户端

客户端源码

在这里插入代码片
```#include <iostream>
//#include <windows.h>
#include <WinSock2.h>
#include <WS2tcpip.h>
using namespace std;
#pragma comment(lib, "Ws2_32.lib")int main() {WSADATA wd;int result;result = WSAStartup(MAKEWORD(2, 2), &wd);if (result != 0) {cout << "WSAStartup error" << endl;return 0;}//创建套接字SOCKET c_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);if (c_socket == INVALID_SOCKET) {cout << "socket error" << endl;return 0;}sockaddr_in c_addr;inet_pton(AF_INET, "127.0.0.1", &c_addr.sin_addr.S_un.S_addr);c_addr.sin_family = AF_INET;c_addr.sin_port = htons(8888);int len = sizeof(c_addr);result = connect(c_socket, (sockaddr*)&c_addr, len);if (result == INVALID_SOCKET) {cout << "connect error" << endl;return 0;}char sendbuf[1024] = { 0 };cout << "client输入数据:";cin >> sendbuf;//sendresult = send(c_socket, sendbuf, sizeof(sendbuf), 0);if (result == SOCKET_ERROR) {cout << "client send error" << endl;return 0;}//recvchar recvbuf[1024] = { 0 };result = recv(c_socket, recvbuf, sizeof(recvbuf), 0);if (result == 0) {cout << "recv error" << endl;return 0;}cout << "servic发送的数据:" << recvbuf << endl;//closeclosesocket(c_socket);WSACleanup();return 0;
}

服务端源码

#include <iostream>
//#include <windows.h>
#include <WinSock2.h>
#include <WS2tcpip.h>
//#include <stdlib.h>
//#include <stdio.h>
using namespace std;
//导入动态库
#pragma comment(lib,"ws2_32.lib")int __cdecl  main(int argc, char** argv) {WSADATA wd; //创建wd的WSADATA对象SOCKET s_socket = INVALID_SOCKET;int result;//初始化winsock//调用WSAStartupresult = WSAStartup(MAKEWORD(2, 2), &wd);if (result != 0) {//printf("WSAStartup 失败：d%\n", result);}//1 创建套接字SOCKET ser_socket = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);//判断套接字是否有效if (ser_socket == INVALID_SOCKET) {cout << "套接字不可用";return 0;}//2 绑定端口和地址 sockaddr_in 是一个结构体sockaddr_in addr;/*	addr.sin_addr.S_un.S_addr = inet_addr("127.0.0.1"); 使用这个会报错*/inet_pton(AF_INET,"127.0.0.1",&addr.sin_addr.S_un.S_addr);addr.sin_family = AF_INET;addr.sin_port = htons(8888);int len = sizeof(addr);result = bind(ser_socket, (LPSOCKADDR)&addr, len);if (result == SOCKET_ERROR) {cout << "socket error"<< result << endl;return 0;}cout << "服务器启动成功，正在等待客户端连接" << endl;//3 监听if (listen(ser_socket, 5) == SOCKET_ERROR) {cout << "listen error" << endl;}FD_SET  read_set;//创建文件描述集合FD_ZERO(&read_set);//清空文件描述集合FD_SET(ser_socket, &read_set);//将监听套接字放入文件描述集合timeval timeout{ 0,0 };//select超时设置while (true) {FD_SET temp_set;FD_ZERO(&temp_set);temp_set = read_set;int select_num = select(0, &temp_set, NULL, NULL, &timeout);if (select_num == SOCKET_ERROR) {continue;}for (int i = 0; i < temp_set.fd_count; i++) {SOCKET s_df = temp_set.fd_array[i];if (s_df == ser_socket) { // 判断监听套接字是否就绪//4 接收连接//获取客户端IP地址和端口sockaddr_in client_addr;client_addr.sin_family = AF_INET;int client_len = sizeof(client_addr);s_socket = accept(ser_socket, (sockaddr*)&client_addr, &client_len);if (s_socket == INVALID_SOCKET) {cout << "accept error" << endl;continue;}				else {cout << "客户端连接成功" << endl;}char ipbuff[100];string remote_host = inet_ntop(AF_INET, &addr.sin_addr.S_un.S_addr, ipbuff, 20);cout << "接收到客户机:" << remote_host << " 端口号:" << addr.sin_port << endl;// 5接收和发送	char recvbuf[1024] = { 0 };result = recv(s_socket, recvbuf, sizeof(recvbuf), 0);if (result == 0 || result == SOCKET_ERROR) {closesocket(s_df);FD_CLR(s_df, &read_set);//从集中清除套接字cout << "结束连接" << result << endl;}cout << "client发送的数据:" << recvbuf << endl;cout << "service输入数据:";char sendbuf[1024] = { 0 };cin >> sendbuf;result = send(s_socket, sendbuf, sizeof(sendbuf), 0);if (result == SOCKET_ERROR) {cout << "service send error" << endl;}if (s_socket == INVALID_SOCKET) {cout << "socket error" << endl;return 0;}}else {}}}while (s_socket) {}// 6关闭closesocket(s_socket);WSACleanup();system("pause");return 0;
}