获得本机的用户名及IP地址函数

#include <cstdlib>
#include <iostream>
#include <conio.h>
#include <stdio.h>
#include <string.h>
#include <winsock2.h> //Windows Sockets函数定义
#include <stdlib.h>
using namespace std;
bool InitSocket(); //初始化Windows Sockets动态连接库
#pragma comment(lib, "Ws2_32.lib")

void GetIP(char ip[32])
{   
  struct hostent  *hp;
  struct in_addr  in;
  char  hostname[32];
  int id=0;// 用于网卡计数
  *ip=0;
  gethostname(hostname,31);//获得主机名
  cout<<hostname<<endl;
  
  if((hp=gethostbyname(hostname))==NULL)
  {
    printf("ERROR: unable get host '%s' ip\n",hostname);
    return;
  };     

  while(hp->h_addr_list[id]!=NULL)
  {
    memcpy(&in.s_addr,hp->h_addr_list[id],sizeof(in.s_addr));
	//cout<<inet_ntoa(in)<<endl;
    strcpy(ip,inet_ntoa(in));
   // printf("ip is %s\n",ip);
    id++;
  }
};

如果在内网中，只能获得内网的IP地址~

下面是可用的服务器端程序，连接后会显示对方的IP地址，并将数据储存到txt中：

#include <cstdlib>
#include <iostream>
#include <conio.h>
#include <stdio.h>
#include <winsock2.h>
#include <time.h>
#include<ctime>
bool InitSocket();
using namespace std;
#pragma comment(lib, "Ws2_32.lib")
char ChangeIntToChar(int num)
{
    char ch;
    if (num<10&&num>=0)
        ch=char(num+48);
    if (num<=15&&num>=10)
        ch=char(num+55);
    return ch;
}
int main(int argc, char *argv[])
{
    struct sockaddr addr;
    int len,off;
    bool over;
    char msg[255];
    SOCKET sock ,sersock;

    if ( !InitSocket() ) return 0; //初始化Window Sockets DLL(ws2_32.dll)
    //创建流Socket：即传输层使用TCP
    sock = socket( AF_INET,SOCK_STREAM,0 );

    if ( sock==INVALID_SOCKET ) //不能创建，返回
    {
        printf("不能创建Socket!");
        getch();
        WSACleanup( ); //卸载Window Sockets DLL
        return 0;
    }

    //设置IP地址和端口号
    ((sockaddr_in*)&addr)->sin_family = AF_INET; //AF_INET:使用Internet 协议
    ((sockaddr_in*)&addr)->sin_port = htons(8080); //服务器端口号3000
    ((sockaddr_in*)&addr)->sin_addr.s_addr = inet_addr("192.168.1.14");//主机地址

    //把套接字与地址绑定
    bind(sock,&addr,sizeof(addr));
    //监听网络连接
    listen(sock,1); //监听连接：1--允许等待队列的长度
    printf("等待客户连接!\n");

    SOCKADDR_IN addrClient;
    len = sizeof(addrClient);

    //接受网络连接，生成新的套接字sersock标识这一连接
    sersock = accept( sock,(SOCKADDR*)&addrClient,&len );
    //从等待队列中检取客户，如队列空则进程挂起
    //如不空，则接受并生成新Socket以表示此连接，而原Socket继续等待新客户
    if (sersock==INVALID_SOCKET)
    {
        DWORD err = WSAGetLastError();
        char txt[100];
        sprintf(txt,"error when accept!---errno:%d",err);
        printf(txt);
        getch();
        WSACleanup( ); //卸载Window Sockets DLL
        return 0;
    }

    printf("有客户连接!\n");
    cout<<"对方的地址为: "<<inet_ntoa(addrClient.sin_addr)<<endl;
    cout<<endl;


    int i=0;
    char temp_L=0;
    char temp_H=0;
    char a,b;
    int j;
    char temp_data[300];
    time_t now_time;
    time_t last_time;
    char Datashow[128];
    char Timeshow[128];
    time_t ltime;
    FILE *fp;

    fp=fopen("D://text.txt","w");
    while (1)
    {

        cout<<"等待数据..."<<endl;
        memset(msg,0,sizeof(msg));
        memset(temp_data,0,sizeof(temp_data));
        last_time= time(NULL);
        len = recv ( sersock,msg,200,0 ); //接收用户信息



        for ( i=0,j=0;i<len;i++)
        {
            temp_L=msg[i]&0x0f;
            temp_H=msg[i]>>4;
            temp_H=temp_H&0x0f;

            a=ChangeIntToChar((int)temp_H);
            b=ChangeIntToChar((int)temp_L);
            temp_data[j++]=a;
            temp_data[j++]=b;

            cout<<a<<b<<" ";

        }

        cout<<endl;
        cout<<temp_data<<endl;
        now_time=time(NULL);

        if ((now_time-last_time)<=0)
            break;
        _strdate( Datashow );
        printf( "OS date:%s\n", Datashow ); //打印当前日期
        fputs(Datashow,fp);
        fputs("  ",fp);


        _strtime( Timeshow );
        printf( "OS time:%s\n", Timeshow ); //打印当前时间
        fputs(Timeshow,fp);
        fputs(" :   \n",fp);

        fputs("\n当前数据是：",fp);
        for (int m=0;m<j;m++)
        {
            fprintf(fp, "%c", temp_data[m]);
            if (m%2!=0)
            {
                fputs(" ",fp);
            }


        }
        fputs("\n\n",fp);
    }
    fclose(fp);
    //关闭套接字
    closesocket(sersock);
    closesocket(sock);
    WSACleanup( ); //卸载Window Sockets DLL
    return 0;
}

bool InitSocket()
{
    WORD wVersionRequested;
    WSADATA wsaData;
    int err;

    wVersionRequested = MAKEWORD( 2, 0 );
    //初始化Windows Sockets DLL,
    err = WSAStartup( wVersionRequested, &wsaData );//加载Winsock DLL到内存
    if ( err != 0 )
    {
        printf("没有Windows Socket动态库!\n");
        getch();
        return false;
    }

    if ( LOBYTE( wsaData.wVersion ) != 2 || HIBYTE( wsaData.wVersion ) != 0 )
    {
        printf("需要Windows Socket 2!\n");
        getch();
        WSACleanup( ); //非winsock 2.0时，卸载Window Sockets DLL
        return false;
    }
    return true;
}