一、介绍

tcp和udp的区别之一，即tcp是有连接的，udp是无连接的，udp收发数据的代码可以独立运行，tcp发数据前必须确保收数据的一方是打开的，否则无法建立连接。

二、收数据

tcpRecv.h

#pragma once
#include<iostream>
#include<winsock.h>
#pragma comment(lib,"ws2_32.lib")
using namespace std;class tcpRecv
{
public:tcpRecv();~tcpRecv();void initialization();void recvData();
public://定义发送缓冲区和接受缓冲区char send_buf[100];char recv_buf[100];//定义服务端套接字，接受请求套接字SOCKET s_server;SOCKET s_accept;//服务端地址客户端地址SOCKADDR_IN server_addr;SOCKADDR_IN accept_addr;
};

tcpRecv.cpp

#include "tcpRecv.h"tcpRecv::tcpRecv()
{initialization();//填充服务端信息server_addr.sin_family = AF_INET;server_addr.sin_addr.S_un.S_addr = htonl(INADDR_ANY);server_addr.sin_port = htons(14555);//创建套接字s_server = socket(AF_INET, SOCK_STREAM, 0);if (bind(s_server, (SOCKADDR *)&server_addr, sizeof(SOCKADDR)) == SOCKET_ERROR) {cout << "套接字绑定失败！" << endl;WSACleanup();}else {cout << "套接字绑定成功！" << endl;}//设置套接字为监听状态if (listen(s_server, SOMAXCONN) < 0) {cout << "设置监听状态失败！" << endl;WSACleanup();}else {cout << "设置监听状态成功！" << endl;}cout << "服务端正在监听连接，请稍候...." << endl;//接受连接请求int len = sizeof(SOCKADDR);s_accept = accept(s_server, (SOCKADDR *)&accept_addr, &len);if (s_accept == SOCKET_ERROR) {cout << "连接失败！" << endl;WSACleanup();}cout << "连接建立，准备接受数据" << endl;
}tcpRecv::~tcpRecv()
{//关闭套接字closesocket(s_server);closesocket(s_accept);//释放DLL资源WSACleanup();
}void tcpRecv::initialization() {//初始化套接字库WORD w_req = MAKEWORD(2, 2);//版本号WSADATA wsadata;int err;err = WSAStartup(w_req, &wsadata);if (err != 0) {cout << "初始化套接字库失败！" << endl;}else {cout << "初始化套接字库成功！" << endl;}//检测版本号if (LOBYTE(wsadata.wVersion) != 2 || HIBYTE(wsadata.wHighVersion) != 2) {cout << "套接字库版本号不符！" << endl;WSACleanup();}else {cout << "套接字库版本正确！" << endl;}//填充服务端地址信息}void tcpRecv::recvData() {//接收数据int recv_len = recv(s_accept, recv_buf, 100, 0);if (recv_len < 0) {cout << "接受失败！" << endl;}else {cout << "接收信息为:" << recv_buf << endl;}
}

main.cpp

#include "tcpRecv.h"int main() {tcpRecv tcp;while (1) {tcp.recvData();}return 0;
}

三、发数据

tcpSend.h

#pragma once
#include<iostream>
#include<string>
#include<winsock.h>
#pragma comment(lib,"ws2_32.lib")
using namespace std;class tcpSend
{
public:tcpSend();~tcpSend();void initialization();void sendData(std::string&data);
public://定义服务端套接字，接受请求套接字SOCKET s_server;//服务端地址客户端地址SOCKADDR_IN server_addr;
};

tcpSend.cpp

#include "tcpSend.h"tcpSend::tcpSend()
{initialization();//填充服务端信息server_addr.sin_family = AF_INET;server_addr.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");server_addr.sin_port = htons(14555);//创建套接字s_server = socket(AF_INET, SOCK_STREAM, 0);if (connect(s_server, (SOCKADDR *)&server_addr, sizeof(SOCKADDR)) == SOCKET_ERROR) {cout << "服务器连接失败！" << endl;WSACleanup();}else {cout << "服务器连接成功！" << endl;}
}tcpSend::~tcpSend()
{//关闭套接字closesocket(s_server);//释放DLL资源WSACleanup();
}void tcpSend::initialization() {//初始化套接字库WORD w_req = MAKEWORD(2, 2);//版本号WSADATA wsadata;int err;err = WSAStartup(w_req, &wsadata);if (err != 0) {cout << "初始化套接字库失败！" << endl;}else {cout << "初始化套接字库成功！" << endl;}//检测版本号if (LOBYTE(wsadata.wVersion) != 2 || HIBYTE(wsadata.wHighVersion) != 2) {cout << "套接字库版本号不符！" << endl;WSACleanup();}else {cout << "套接字库版本正确！" << endl;}//填充服务端地址信息}void tcpSend::sendData(std::string&data) {int send_len = send(s_server, data.c_str(), sizeof(data), 0);if (send_len < 0) {cout << "发送失败！" << endl;}else {std::cout << "send data：" << data.c_str() << std::endl;}}

main.cpp

#include "tcpSend.h"int main() {tcpSend tcp;for (int i = 0; i < 100; i++) {std::string s = "test " + std::to_string(i);tcp.sendData(s);Sleep(1000);}return 0;
}