建立一个简易的TCP客户端与服务端

TCP服务端

分为一下六步：

1. 建立一个socket 套接字
2. bind 绑定用于接受客户端连接的网络接口
3. listen 监听网络端口
4. accept 等待接受客户端连接
5. send 向客户端发送一条数据
6. 关闭套接字closesocket

#define WIN32_LEAN_AND_MEAN
#define _WINSOCK_DEPRECATED_NO_WARNINGS

#include <iostream>
#include <WinSock2.h>
#include <Windows.h>
//只有在WIN里可以
#pragma comment(lib,"ws2_32.lib")

using namespace std;

int main() {
	//启动Windows socket 2.x环境
	WORD ver = MAKEWORD(2, 2);
	WSADATA dat;
	WSAStartup(ver, &dat);
	// 用Socket API 建立一个简易的TCP服务端
	// 1 建立一个socket 套接字
	SOCKET _sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	// 2 bind 绑定用于接受客户端连接的网络接口
	sockaddr_in _sin = {};
	_sin.sin_family = AF_INET;
	_sin.sin_port = htons(4567);// host to net unsigned short
	_sin.sin_addr.S_un.S_addr = INADDR_ANY;//inet_addr("127.0.0.1");
	if (bind(_sock, (sockaddr*)&_sin, sizeof(_sin)) == SOCKET_ERROR) {
		//绑定错误
		cout << "绑定网络端口失败..." << endl;
	}
	else {
		cout << "绑定网络端口成功..." << endl;
	}
	//3 listen 监听网络端口
	if (SOCKET_ERROR == listen(_sock, 5)) {
		cout << "监听网络端口失败..." << endl;
	}
	else {
		cout << "监听网络端口成功..." << endl;
	}
	//4 accept 等待接受客户端连接
	sockaddr_in clientAddr = {};
	int nAddrLen = sizeof(sockaddr_in);
	SOCKET _cSock = INVALID_SOCKET;
	char msgBuf[] = "Hello ,I'm Server.";
	while (true) {
		_cSock = accept(_sock, (sockaddr*)&clientAddr, &nAddrLen);
		if (_cSock == INVALID_SOCKET) {
			cout << "接受到无效客户端SOCKET..." << endl;
		}
		cout << "新客户端加入：IP =" << inet_ntoa(clientAddr.sin_addr) << endl;
		//5 send 向客户端发送一条数据
		send(_cSock, msgBuf, strlen(msgBuf) + 1, 0);
	}
	//6 关闭套接字closesocket
	closesocket(_sock);
	//7 清除windows socket环境
	WSACleanup();
	//保留界面
	getchar();
	return 0;
}

TCP服务端

分为四步：

1. 建立一个socket
2. 连接服务器 connect
3. 接受服务器信息 recv
4. 关闭套接字closesocket

#define WIN32_LEAN_AND_MEAN
#define _WINSOCK_DEPRECATED_NO_WARNINGS

#include <iostream>
#include <WinSock2.h>
#include <Windows.h>
//只有在WIN里可以
#pragma comment(lib,"ws2_32.lib")

using namespace std;

int main() {
	//启动Windows socket 2.x环境
	WORD ver = MAKEWORD(2, 2);
	WSADATA dat;
	WSAStartup(ver, &dat);
	// 用Socket API 建立一个简易的TCP服务端

	// 1 建立一个socket
	SOCKET _sock = socket(AF_INET, SOCK_STREAM, 0);
	if (INVALID_SOCKET == _sock) {
		cout << "建立Socket失败..." << endl;
	}
	else {
		cout << "建立Socket成功..." << endl;
	}
	// 2 连接服务器 connect
	sockaddr_in _sin = {};
	_sin.sin_family = AF_INET;
	_sin.sin_port = htons(4567);
	_sin.sin_addr.S_un.S_addr = inet_addr("127.0.0.1");
	int ret = connect(_sock, (sockaddr*)&_sin, sizeof(sockaddr_in));
	if (SOCKET_ERROR == ret) {
		cout << "连接Socket失败..." << endl;
	}
	else {
		cout << "连接Socket成功..." << endl;
	}
	//3 接受服务器信息 recv
	char recvBuf[256] = {};
	int nlen = recv(_sock, recvBuf, 256, 0);
	if (nlen > 0) {
		cout << "接收到数据为：" << recvBuf << endl;
	}
	// 4 关闭套接字closesocket
	closesocket(_sock);
	// 5 清除windows socket环境
	WSACleanup();
	//保留界面
	getchar();
	return 0;
}

运行截图

服务端

客户端