p2p聊天程序C++

/********************************************************************
数据报套接字的对等模式实例：首先输入要发送给对方的消息，然后发送给对方，
再接收对方发送过来的消息，如此循环地进行发送-接收
********************************************************************/
#include <string.h>
#include <stdio.h>
#include <winsock2.h>
#pragma comment(lib, "Ws2_32.lib")
void main()
{
WSADA TA wsaData;
if( WSAStartup(MAKEWORD(1,1), &wsaData) ) //调用初始化函数，版本号为1.1 {
printf("Could not load windows sockets DLL\n");
return;
}
//创建数据报套接字
SOCKET s = socket(AF_INET,SOCK_DGRAM, 0);
if(s==INV ALID_SOCKET)
{
printf("invalid socket\n");
WSACleanup();
return;
}
//本地地址信息
sockaddr_in hostAddress;
int addressLen = sizeof(sockaddr_in);
memset((void*)&hostAddress, 0, addressLen); //清空sockaddr结构
hostAddress.sin_family = AF_INET; //Internet协议族
int port;
printf("local port(1024-65535): ");
scanf("%d",&port);
hostAddress.sin_port = htons(port); //端口
hostAddress.sin_addr.s_addr=INADDR_ANY;
//对方地址信息
sockaddr_in remoteAddress;
memset((void*)&remoteAddress, 0, addressLen); //清空sockaddr结构
remoteAddress.sin_family = AF_INET; //Internet协议族
printf("remote port(1024-65535): ");
scanf("%d",&port);
remoteAddress.sin_port = htons(port); //对方端口
remoteAddress.sin_addr.s_addr=inet_addr("127.0.0.1"); //对方IP地址
//将本地地址绑定到套接字
if(bind(s,(sockaddr*)&hostAddress,addressLen))
{
printf("bind failed\n");
WSACleanup();
return;
}
char buf[1024],msg[1024];
char myName[30];
printf("请输入您的昵称：");
scanf("%s",myName);
strcat(myName, ": ");
sockaddr_in fromAddress;
while(1)
{
printf("请输入要发送的消息:");
scanf("%s",msg);
strcpy(buf,myName);
strcat(buf, msg);
//发送数据给对方
if( sendto(s,buf,strlen(buf), 0, (sockaddr*)&remoteAddress, addressLen) == SOCKET_ERROR )
{
printf("sendto2 failed\n");
break;
}
//接收数据并显示
int n=recvfrom(s,buf,sizeof(buf),0, (sockaddr*)&fromAddress, &addressLen);
if(n>0)
{
buf[n]=0; //理解为什么这么做
printf("Reveived from %s\n",buf);
}
else
printf("erro: %d\n", n);
//确保下次是回复给对方
if(memcmp(&remoteAddress, &fromAddress,addressLen)) memcpy(&remoteAddress,&fromAddress, addressLen);
}
closesocket(s);
WSACleanup();
}。