windows C++ socket server

* SocketDemo.cpp

/*****************************************************************************************************************************
*1、加载套接字库，创建套接字（WSAStartup() / socket()）;
*2、绑定套接字到一个IP地址和一个端口上（bind()）;
*3、将套接字设置为监听模式等待连接请求；
* 4、请求到来之后，接受连接请求，返回一个新的对应于此次连接的套接字(accept());
*5、用返回的套接字和客户端进行通信（send() / recv()）;
*6、返回，等待另一个连接请求
* 7、关闭套接字，关闭加载的套接字库(closesocket() / WSACleanup());
*****************************************************************************************************************************/
#include <iostream>
#include <WinSock2.h>
#include <ws2tcpip.h>
using namespace std;
#pragma comment(lib,"ws2_32.lib")

void reverse(char* p, char* q) {
	if (p > q) { swap(p, q); }
	char t = NULL;
	for (; p < q; p++, q--) {
		t = *p;
		*p = *q;
		*q = t;
	}
}

void ntoa(char *addr, ULONG ip) {
	UINT8 a, b, c, d;
	char* p = addr, * q = NULL;

	d = ip >> 24;
	c = (ip & 0x00ffffff) >> 16;
	b = (ip & 0x0000ffff) >> 8;
	a = (ip & 0x000000ff);

	q = p;
	do {
		*p = a % 10 + 48;
		a /= 10;
		p++;
	} while (a > 0);
	reverse(q, p - 1);
	*p++ = '.';

	q = p;
	do {
		*p = b % 10 + 48;
		b /= 10;
		p++;
	} while (b > 0);
	reverse(q, p - 1);
	*p++ = '.';

	q = p;
	do {
		*p = c % 10 + 48;
		c /= 10;
		p++;
	} while (c > 0);
	reverse(q, p - 1);
	*p++ = '.';

	q = p;
	do {
		*p = d % 10 + 48;
		d /= 10;
		p++;
	} while (d > 0);
	reverse(q, p - 1);
	*p = '\0';
}

int main()
{
	//初始化WSA
	WORD sockVersion = MAKEWORD(2, 2);
	WSADATA wsaData;//WSADATA结构体变量的地址值
	const int port = 8090;

	//int WSAStartup(WORD wVersionRequested, LPWSADATA lpWSAData);
	//成功时会返回0，失败时返回非零的错误代码值
	if (WSAStartup(sockVersion, &wsaData) != 0)
	{
		cout << "WSAStartup() error!" << endl;
		return 0;
	}

	//创建套接字
	SOCKET slisten = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
	if (slisten == INVALID_SOCKET)
	{
		cout << "socket error !" << endl;
		return 0;
	}

	//绑定IP和端口
	sockaddr_in sin;//ipv4的指定方法是使用struct sockaddr_in类型的变量
	sin.sin_family = AF_INET;
	sin.sin_port = htons(port);//设置端口。htons将主机的unsigned short int转换为网络字节顺序
	sin.sin_addr.S_un.S_addr = INADDR_ANY;//IP地址设置成INADDR_ANY，让系统自动获取本机的IP地址
	//bind函数把一个地址族中的特定地址赋给scket。
	if (bind(slisten, (LPSOCKADDR)&sin, sizeof(sin)) == SOCKET_ERROR)
	{
		cout << "bind error !" << WSAGetLastError() << endl;
	}

	//开始监听
	if (listen(slisten, SOMAXCONN) == SOCKET_ERROR)
	{
		cout << "listen error !" << endl;
		return -1;
	}

	//循环接收数据
	SOCKET sclient;
	sockaddr_in remoteAddr;//sockaddr_in常用于socket定义和赋值,sockaddr用于函数参数
	int nAddrlen = sizeof(remoteAddr);
	char revData[255];
	char addr[16];
	while (true)
	{
		cout << "等待连接... 0.0.0.0:" << port << endl;
		sclient = accept(slisten, (sockaddr*)&remoteAddr, &nAddrlen);
		if (sclient == INVALID_SOCKET)
		{
			cout << "accept error !" << endl;
			continue;
		}
		// inet_ntop(AF_INET, (sockaddr*)&remoteAddr, ipAddr, 16);
		ntoa(addr, remoteAddr.sin_addr.s_addr);
		cout << "接收到一个连接：" << addr << endl;
		// 接收数据
		int ret = recv(sclient, revData, 255, 0);
		if (ret > 0 && ret < 255)
		{
			revData[ret] = 0x00;
			cout << revData << endl;
		}
		// 发送数据
		const char* sendData = "你好，TCP客户端！\n";
		send(sclient, sendData, (int)strlen(sendData), 0);
		closesocket(sclient);
	}
	closesocket(slisten);
	WSACleanup();
	system("pause");
	//return 0;
}

// Tips for Getting Started: 
//   1. Use the Solution Explorer window to add/manage files
//   2. Use the Team Explorer window to connect to source control
//   3. Use the Output window to see build output and other messages
//   4. Use the Error List window to view errors
//   5. Go to Project > Add New Item to create new code files, or Project > Add Existing Item to add existing code files to the project
//   6. In the future, to open this project again, go to File > Open > Project and select the .sln file

telnet连接测试:

手机、电脑连同一个wifi，代理设置成电脑的ip

无线局域网适配器 WLAN:

   连接特定的 DNS 后缀 . . . . . . . :
   IPv6 地址 . . . . . . . . . . . . : 240e:878:d5:b560:550b:562c:730d:9764
   临时 IPv6 地址. . . . . . . . . . : 240e:878:d5:b560:14d2:fbfb:711e:3b39
   本地链接 IPv6 地址. . . . . . . . : fe80::a184:41cd:9359:4468%22
   IPv4 地址 . . . . . . . . . . . . : 192.168.1.100
   子网掩码  . . . . . . . . . . . . : 255.255.255.0
   默认网关. . . . . . . . . . . . . : fe80::1234%22
                                       192.168.1.1

 服务端接收到的数据:

等待连接... 0.0.0.0:8090
接收到一个连接：192.168.1.102
CONNECT dict.youdao.com:443 HTTP/1.1
Host: dict.youdao.com
Proxy-Connection: keep-alive
Connection: keep-alive