server

#include <Winsock2.h>
#include <stdio.h>
#include <string>
#include <stdlib.h>
#include <bits/stdc++.h>
#define DEFAULT_PORT 5060
#define BUFFER_LENGTH 1024
using namespace std;
string GetLocalIpAddress()
{
	WORD wVersionRequested = MAKEWORD(2, 2);

	WSADATA wsaData;
	if (WSAStartup(wVersionRequested, &wsaData) != 0)
		return "";

	char local[255] = {0};
	gethostname(local, sizeof(local));
	hostent* ph = gethostbyname(local);
	if (ph == NULL)
		return "";

	in_addr addr;
	memcpy(&addr, ph->h_addr_list[0], sizeof(in_addr)); // ÕâÀï½ö»ñÈ¡µÚÒ»¸öip

	string localIP;
	localIP.assign(inet_ntoa(addr));

	WSACleanup();
	return localIP;
}
struct user
{
    int port;
    char ip[100];
    SOCKET sc;
    struct sockaddr_in ser;
    int isend,ilen;

    user(int _port,char* _ip)
    {
        port=5060;
        strncpy(ip, _ip, sizeof(ip));
        ser.sin_family = AF_INET;
        ser.sin_port = htons(port);
        ser.sin_addr.s_addr=inet_addr(ip);
        sc = socket(AF_INET,SOCK_DGRAM,0);
        if(sc==INVALID_SOCKET)
        {
            printf("socket()Failed:%d\n",WSAGetLastError());
        }
        ilen = sizeof(ser);
    }
};
vector<user>u;
int vis[1000001];
int main()
{
     char date[100];
    strcpy (date, const_cast<char*>(GetLocalIpAddress().c_str()));
    int iPort = DEFAULT_PORT;
    WSADATA  wsaData;
    SOCKET   sSocket;
    int iLen;
    int iSend;
    int iRecv;
    char send_buf[BUFFER_LENGTH];
    char recv_buf[BUFFER_LENGTH];
    struct sockaddr_in ser,cli;
    printf("-----------------------\n");
    printf("Server waiting!\n");
    printf("------------------------\n");
    if(WSAStartup(MAKEWORD(2,2),&wsaData)!=0)
    {
        printf("Failed to load Winsock.\n");
        return 0;
    }
    sSocket = socket(AF_INET,SOCK_DGRAM,0);
    if(sSocket == INVALID_SOCKET)
    {
        printf("socket()Failed:%d\n",WSAGetLastError());
        return 0;
    }
    ser.sin_family = AF_INET;
    ser.sin_port = htons(iPort);
    ser.sin_addr.s_addr=htonl(INADDR_ANY);
    if(bind(sSocket,(LPSOCKADDR)&ser,sizeof(ser))==SOCKET_ERROR)
    {
        printf("bind()Failed:%d\n",WSAGetLastError());
        return 0;
    }
    iLen = sizeof(cli);
    while(1)
    {
        memset(vis,0,sizeof(vis));
        memset(recv_buf,0,sizeof(recv_buf));
        iRecv=recvfrom(sSocket,recv_buf,BUFFER_LENGTH,0,(SOCKADDR*)&cli,&iLen);
        if(iRecv==SOCKET_ERROR)
        {
            printf("recvfrom():%d\n",WSAGetLastError());
            break;
        }
        else if(iRecv==0)break;
            else
            {
                user v(ntohs(cli.sin_port),inet_ntoa(cli.sin_addr));
                printf("Accepted client IP:[%s],port:[%d]\n",inet_ntoa(cli.sin_addr),ntohs(cli.sin_port));
                int flag=0;
                for(int j=0;j<u.size();j++)
                {
                	//cout<<strcmp(u[j].ip,v.ip)<<endl;
                	if(strcmp(u[j].ip,v.ip)==0)flag=1; 
				}
                if(!flag) u.push_back(v);
                if(recv_buf[0]=='#')
                {
                    printf("client has already quit!\n");
                    vector<user>::iterator itor;
                    for(itor=u.begin();itor!=u.end();itor++)
                    {
                        if((*itor).port==v.port) itor = u.erase(itor);
                    }
                }
                else
                {
                	
                    for(int i=0;i<u.size();i++)
                    {
                        u[i].isend=sendto(u[i].sc,recv_buf,sizeof(recv_buf),0,(struct sockaddr*)&u[i].ser,u[i].ilen);
                        if(u[i].isend==SOCKET_ERROR)
                        {
                            printf("sendto()Failed:%d\n",WSAGetLastError());
                            return 0;
                        }
                    }
                    printf("%s\n",recv_buf);
                }
// else if(cli.sin_addr.s_addr==inet_addr(date))printf("Íõ³¿ÄÝ:%s\n",recv_buf);
// else printf("Ê·ÖÐÎä:%s\n",recv_buf);
              // printf("Accepted client IP:[%s],port:[%d]\n",inet_ntoa(cli.sin_addr),ntohs(cli.sin_port));
            }

    }
    closesocket(sSocket);
    WSACleanup();
    return 0;
}

send

#include <Winsock2.h>
#include <stdio.h>
#include <string>
#define DEFAULT_PORT 5060
#define DATA_BUFFER 1024
using namespace std;
int main(int argc,char *argv[])
{
    WSADATA wsaData;
    SOCKET sClient,sSelf;
    int iPort = DEFAULT_PORT;
    int iLen,iSend,iRecv;
    char buf[DATA_BUFFER];
    char recv_buf[DATA_BUFFER];
    char send_buf[DATA_BUFFER]="Hello i am a cilent!";
    struct sockaddr_in ser,ser2;
    if(argc<2)
    {
        printf("Usage:client [server IP address]\n");
        return 0;
    }
    memset(recv_buf,0,sizeof(recv_buf));
    if(WSAStartup(MAKEWORD(2,2),&wsaData)!=0)
    {
        printf("Failed to load Winsock.\n");
        return 0;
    }
    ser.sin_family = AF_INET;
    ser.sin_port = htons(iPort);
    ser.sin_addr.s_addr=inet_addr(argv[1]);

    sClient = socket(AF_INET,SOCK_DGRAM,0);
    if(sClient==INVALID_SOCKET)
    {
    	 printf("socket()Failed:%d\n",WSAGetLastError());
        return 0;
    }

    iLen = sizeof(ser);
    while(1)
    {
    gets(send_buf);
    iSend=sendto(sClient,send_buf,sizeof(send_buf),0,(struct sockaddr*)&ser,iLen);
    if(iSend==SOCKET_ERROR)
    {
        printf("sendto()Failed:%d\n",WSAGetLastError());
        return 0;
    }
    else if(iSend==0) return 0;

    if(send_buf[0]=='#') break;
    }
    /*iRecv=recvfrom(sClient,recv_buf,sizeof(recv_buf),0,(struct sockaddr*)&ser,&iLen); if(iRecv==SOCKET_ERROR) { printf("recvfrom()Failed:%d\n",WSAGetLastError()); return 0; } else if(iRecv==0) return 0; else { printf("%s",recv_buf); printf("recvfrom()succeeded!\n"); printf("-------------------\n"); }//*/
    closesocket(sClient);
    WSACleanup();

    return 0;
}

#include <Winsock2.h>
#include <stdio.h>
#include <string>
#include <stdlib.h>
#define DEFAULT_PORT 5060
#define BUFFER_LENGTH 1024
using namespace std;
string GetLocalIpAddress()
{
	WORD wVersionRequested = MAKEWORD(2, 2);

	WSADATA wsaData;
	if (WSAStartup(wVersionRequested, &wsaData) != 0)
		return "";

	char local[255] = {0};
	gethostname(local, sizeof(local));
	hostent* ph = gethostbyname(local);
	if (ph == NULL)
		return "";

	in_addr addr;
	memcpy(&addr, ph->h_addr_list[0], sizeof(in_addr)); // ÕâÀï½ö»ñÈ¡µÚÒ»¸öip

	string localIP;
	localIP.assign(inet_ntoa(addr));

	WSACleanup();
	return localIP;
}
int main()
{
     char date[100];
    strcpy (date, const_cast<char*>(GetLocalIpAddress().c_str()));
    int iPort = DEFAULT_PORT;
    WSADATA  wsaData;
    SOCKET   sSocket;
    int iLen;
    int iSend;
    int iRecv;
    char send_buf[BUFFER_LENGTH];
    char recv_buf[BUFFER_LENGTH];
    struct sockaddr_in ser,cli;
    printf("-----------------------\n");
    printf("Server waiting!\n");
    printf("------------------------\n");
    if(WSAStartup(MAKEWORD(2,2),&wsaData)!=0)
    {
        printf("Failed to load Winsock.\n");
        return 0;
    }
    sSocket = socket(AF_INET,SOCK_DGRAM,0);
    if(sSocket == INVALID_SOCKET)
    {
        printf("socket()Failed:%d\n",WSAGetLastError());
        return 0;
    }
    ser.sin_family = AF_INET;
    ser.sin_port = htons(iPort);
    ser.sin_addr.s_addr=htonl(INADDR_ANY);
    if(bind(sSocket,(LPSOCKADDR)&ser,sizeof(ser))==SOCKET_ERROR)
    {
        printf("bind()Failed:%d\n",WSAGetLastError());
        return 0;
    }
    iLen = sizeof(cli);
    while(1)
    {
        memset(recv_buf,0,sizeof(recv_buf));
        iRecv=recvfrom(sSocket,recv_buf,BUFFER_LENGTH,0,(SOCKADDR*)&cli,&iLen);
        if(iRecv==SOCKET_ERROR)
        {
            printf("recvfrom():%d\n",WSAGetLastError());
            break;
        }
    else if(iRecv==0)break;
            else
            {
                if(recv_buf[0]=='#') printf("client has already quit!\n");
                else printf("ȺÏûÏ¢£º%s\n",recv_buf);
               // printf("Accepted client IP:[%s],port:[%d]\n",inet_ntoa(cli.sin_addr),ntohs(cli.sin_port));
            }
    }
    closesocket(sSocket);
    WSACleanup();
    return 0;
}