TCP通信

//网络套接字编程实例，服务器端，TCP通信。
#include <WinSock2.h>
#pragma comment(lib,"ws2_32.lib")
#include <iostream>
#include <windows.h>
using namespace std;

int main()
{
WSADATA wsaData;
WSAStartup(MAKEWORD(2,2),&wsaData);  //初始化版本
SOCKET sList = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);  //初始化socket
if (sList == INVALID_SOCKET) //判断socket是否建立成功
{
cout << "socket error\n";
}
else
{
cout << "socket success\n";
}
sockaddr_in asd;   //申明bind中addr参数，这是申明，一个结构体。
asd.sin_family = AF_INET;        //设置结构体，必须是：AF_INET
asd.sin_port = htons(1990);      //指定TCP或UDP通信服务端口号，htons函数将主机无符号短整型转换成网络字节顺序，1990是本地监听的端口号。
asd.sin_addr.S_un.S_addr = INADDR_ANY; //INADDR_ANY表示所有可用地址
if (bind(sList, (LPSOCKADDR)&asd, sizeof(asd)) == SOCKET_ERROR) //绑定本地IP和端口
{
cout << "bind error";
closesocket(sList);
return 0;
}
if (listen(sList, 5) == SOCKET_ERROR)
{
cout << "listen error";
closesocket(sList);
return 0;
}//监听,5为连接最数,注意listen只支持上面的SOCK_STREAM也就是TCP，UDP不用条用此函数。

// 循环接受客户的连接请求
sockaddr_in remoteAddr;
SOCKET sClient;
int nAddrlen = sizeof(remoteAddr);
char revData[255];
while (1)
{
// 接受一个新连接
sClient = accept(sList, (SOCKADDR*)&remoteAddr, &nAddrlen);
//错误
if (sClient == INVALID_SOCKET)
{
cout << "accept error";
continue;
}
//打印出连接者的ip
cout << " 接受到一个连接：" << inet_ntoa(remoteAddr.sin_addr)<<"\n";
int ret = recv(sClient, revData, 255, 0);
if (ret > 0)
{
//为了防止打印出错，把字符串结尾设成0x00
revData[ret] = 0x00;
cout<<revData;
}
//发送给客户端数据
char *buff = "握手，我是来自服务端的信息，TCP建立成功\n";
send(sClient, buff, strlen(buff), 0);
closesocket(sClient);
}
closesocket(sList);
system("pause");
return 0;
}

//网络套接字编程实例，客户端。
#include <WinSock2.h>
#pragma comment(lib,"ws2_32.lib")
#include <iostream>
#include <windows.h>
#include <WS2tcpip.h>
using namespace std;

int main()
{
WSADATA wsaData;
WSAStartup(MAKEWORD(2, 2), &wsaData);  //初始化版本
SOCKET sList = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);  //初始化socket
if (sList == INVALID_SOCKET) //判断socket是否建立成功
{
cout << "socket error\n";
}
else
{
cout << "socket success\n";
}
sockaddr_in asd;   //申明bind中addr参数，这是申明，一个结构体。
asd.sin_family = AF_INET;        //设置结构体，必须是：AF_INET
asd.sin_port = htons(1990);      //指定TCP或UDP通信服务端口号，htons函数将主机无符号短整型转换成网络字节顺序，1990是本地监听的端口号。
asd.sin_addr.S_un.S_addr = inet_addr("127.0.0.1"); //INADDR_ANY表示所有可用地址
if (connect(sList, (sockaddr*)&asd, sizeof(asd)) == SOCKET_ERROR)
{
cout<<"connect error\n";
closesocket(sList);
return 0;
}
char *buff = "我是来自客户端的信息";
int nAddrlen = sizeof(asd);
char revData[255];
send(sList, buff, strlen(buff), 0);
int ret = recv(sList, revData, 255, 0);
if (ret > 0)
{
revData[ret] = 0x00;
cout << revData;
}
closesocket(sList);
WSACleanup();
system("pause");
return 0;
}