转载：c++获取本机IP地址

windows下获取IP地址的两种方法；

一种可以获取IPv4和IPv6，但是需要WSAStartup；

一种只能取到IPv4，但是不需要WSAStartup；

如下：

方法一：(可以获取IPv4和IPv6)

#define _WINSOCK_DEPRECATED_NO_WARNINGS
#include <Winsock2.h>
#include <stdio.h>
#include <iostream>
#include <cstring>
#include<ws2tcpip.h>
#pragma comment(lib, "ws2_32.lib ")  //linking to the library
using namespace std;
int get_ip()
{
    struct addrinfo *ailist, *aip;
    struct addrinfo hint;
    struct sockaddr_in6 *sinp6;
    PHOSTENT hostinfo;
    char hostname[] = {}; //主机名
    char *port = "";      //端口号
    const char *addr;
    int ilRc;
    gethostname(hostname, sizeof(hostname));
    if((hostinfo = gethostbyname(hostname)) == NULL) //获得本地ipv4地址
    {
        errno = GetLastError();
        fprintf(stderr,"gethostbyname Error:%d\n", errno);
        return ;
    }
    LPCSTR ip;
    while(*(hostinfo->h_addr_list) != NULL) //输出ipv4地址
    {
        ip = inet_ntoa(*(struct in_addr *) *hostinfo->h_addr_list);
        printf("ipv4 addr = %s\n\n", ip);
        hostinfo->h_addr_list++;
    }
    hint.ai_family = AF_INET6;        //hint 的限定设置
    hint.ai_socktype = SOCK_STREAM;   //这里可是设置 socket type    比如  SOCK_DGRAM
    hint.ai_flags = AI_PASSIVE;       // flags 的标志很多。常用的有AI_CANONNAME;
    hint.ai_protocol = ;             //设置协议  一般为0，默认
    hint.ai_addrlen = ;              //下面不可以设置，为0，或者为NULL
    hint.ai_canonname = NULL;
    hint.ai_addr = NULL;
    hint.ai_next = NULL;
    ilRc = getaddrinfo(hostname, port, &hint, &ailist); //通过主机名获得地址信息
    if (ilRc < )
    {
        char str_error[];
        strcpy(str_error, (char *)gai_strerror(errno));
        printf("str_error = %s", str_error);
        return ;
    }
    if(ailist == NULL)
    {
        printf("sorry not find the IP address,please try again \n");
    }
    for (aip = ailist; aip != NULL; aip = aip->ai_next) //显示获取的信息
    {
        aip->ai_family == AF_INET6;
        sinp6 = (struct sockaddr_in6 *)aip->ai_addr;    //为什么是for 循环 ，先向下看
        int i;
        printf("ipv6 addr = ");
        for(i = ; i < ; i++)
        {
            if(((i-)%) && (i>))
            {
                printf(":");
            }
            printf("%02x",sinp6->sin6_addr.u.Byte[i]);
        }
        printf(" \n");
        printf(" \n");
    }
    while();
}
int main(){

    WORD wVersionRequested;
    WSADATA wsaData;
    int err;
    wVersionRequested = MAKEWORD( ,  );
    err = WSAStartup( wVersionRequested, &wsaData );//initiate the ws2_32.dll and match the version
    if ( err !=  )
    {
        return ;
    }
    if ( LOBYTE( wsaData.wVersion ) !=  ||   //if the version is not matched ,then quit and terminate the ws3_32.dll
        HIBYTE( wsaData.wVersion ) !=  )
    {
        WSACleanup( );
        return ;
    }
    get_ip();
    WSACleanup( );
    return ;
}

方法二：(只能取到IPv4)

//#define _WINSOCK_DEPRECATED_NO_WARNINGS
#include <WinSock2.h>
#include <Iphlpapi.h>
#include <iostream>
using namespace std;
#pragma comment(lib,"Iphlpapi.lib") //需要添加Iphlpapi.lib库
//#pragma comment(lib, "ws2_32.lib")

int main(int argc, char* argv[])
{
    //PIP_ADAPTER_INFO结构体指针存储本机网卡信息
    PIP_ADAPTER_INFO pIpAdapterInfo = new IP_ADAPTER_INFO();
    //得到结构体大小,用于GetAdaptersInfo参数
    unsigned long stSize = sizeof(IP_ADAPTER_INFO);
    //调用GetAdaptersInfo函数,填充pIpAdapterInfo指针变量;其中stSize参数既是一个输入量也是一个输出量
    int nRel = GetAdaptersInfo(pIpAdapterInfo, &stSize);
    //记录网卡数量
    DWORD netCardNum = 0;
    GetNumberOfInterfaces(&netCardNum);
    cout << "网卡数量：" << netCardNum<< endl; netCardNum = 0;
    //记录每张网卡上的IP地址数量
    int IPnumPerNetCard = 0;
    if (ERROR_BUFFER_OVERFLOW == nRel)
    {
        //如果函数返回的是ERROR_BUFFER_OVERFLOW
        //则说明GetAdaptersInfo参数传递的内存空间不够,同时其传出stSize,表示需要的空间大小
        //这也是说明为什么stSize既是一个输入量也是一个输出量
        //释放原来的内存空间
        delete pIpAdapterInfo;
        //重新申请内存空间用来存储所有网卡信息
        pIpAdapterInfo = (PIP_ADAPTER_INFO)new BYTE[stSize];
        //再次调用GetAdaptersInfo函数,填充pIpAdapterInfo指针变量
        nRel = GetAdaptersInfo(pIpAdapterInfo, &stSize);
    }
    if (ERROR_SUCCESS == nRel)
    {
        //输出网卡信息
        //可能有多网卡,因此通过循环去判断
        while (pIpAdapterInfo)
        {
            cout << "网卡序号：" << ++netCardNum <<"\t"<<pIpAdapterInfo->Index << endl;
            cout << "网卡名称：" << pIpAdapterInfo->AdapterName << endl;
            cout << "网卡描述：" << pIpAdapterInfo->Description << endl;
            cout << "网卡类型：";
            switch (pIpAdapterInfo->Type)
            {
            case MIB_IF_TYPE_OTHER:        cout << "OTHER" << endl; break;
            case MIB_IF_TYPE_ETHERNET:    cout << "ETHERNET" << endl; break;
            case MIB_IF_TYPE_TOKENRING:    cout << "TOKENRING" << endl; break;
            case MIB_IF_TYPE_FDDI:        cout << "FDDI" << endl; break;
            case MIB_IF_TYPE_PPP:        cout << "PPP" << endl; break;
            case MIB_IF_TYPE_LOOPBACK:    cout << "LOOPBACK" << endl; break;
            case MIB_IF_TYPE_SLIP:        cout << "SLIP" << endl; break;
            default:                    cout << "" << endl; break;
            }
            cout << "网卡MAC地址：";
            for (DWORD i = 0; i < pIpAdapterInfo->AddressLength; i++)
                if (i < pIpAdapterInfo->AddressLength - 1)
                {
                    printf("%02X-", pIpAdapterInfo->Address[i]);
                }
                else
                {
                    printf("%02X\n", pIpAdapterInfo->Address[i]);
                }
            cout << "网卡IP地址如下：" << endl;
            IPnumPerNetCard = 0;
            //可能网卡有多IP,因此通过循环去判断
            IP_ADDR_STRING *pIpAddrString = &(pIpAdapterInfo->IpAddressList);
            do
            {
                cout << "该网卡上的IP数量：" << ++IPnumPerNetCard << endl;
                cout << "IP 地址：" << pIpAddrString->IpAddress.String << endl;
                cout << "子网掩码：" << pIpAddrString->IpMask.String << endl;
                cout << "网关地址：" << pIpAdapterInfo->GatewayList.IpAddress.String << endl;
                pIpAddrString = pIpAddrString->Next;
            } while (pIpAddrString);
            pIpAdapterInfo = pIpAdapterInfo->Next;
            cout << "--------------------------------------------------------------------" << endl;
        }

    }
    //释放内存空间
    if (pIpAdapterInfo)
    {
        delete pIpAdapterInfo;
    }
    return 0;
}

Linux下,详见:http://www.cnblogs.com/lzpong/p/6956439.html