C/C++ 获取自身IP与域名片段的示例代码

#include <stdio.h>
#include <stdlib.h>
#include <WinSock2.h>
#pragma comment(lib, "ws2_32.lib")

// 变量法判断
void GetA()
{
	DWORD dwSmallNum = 0x01020304;
	if (*(BYTE *)&dwSmallNum == 0x04)
		printf("小端字节序 \n");
	else
		printf("大端字节序 \n");
}

// 直接转换法判断
void GetB()
{
	DWORD dwSmallNum = 0x01020304;
	if (dwSmallNum == htonl(dwSmallNum))
		printf("大端字节序 \n");
	else
		printf("小端字节序 \n");
}

int main(int argc, char *argv[])
{
	GetA();
	GetB();

	system("pause");
	return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <WinSock2.h>
#pragma comment(lib, "ws2_32.lib")

BOOL GetHostByName(char * HostName)
{
	WSADATA wsaData;
	if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
		return FALSE;

	struct hostent *ptr = gethostbyname(HostName);
	if (!ptr){ return FALSE; }

	printf("地址类型: %s \n", (ptr->h_addrtype == AF_INET) ? "IPV4" : "IPV6");

	for (int i = 0; ptr->h_aliases[i]; i++){
		printf("别名 [%d]: %s \n", i + 1, ptr->h_aliases[i]);
	}

	for (int i = 0; ptr->h_addr_list[i]; i++){
		printf("IP地址 [%d]: %s \n", i + 1, inet_ntoa(*(struct in_addr*)ptr->h_addr_list[i]));
	}
	WSACleanup();
	return TRUE;
}

int main(int argc ,char *argv[])
{
	GetHostByName("www.baidu.com");
	system("pause");
	return 0;
}

#include <stdio.h>
#include <stdlib.h>
#include <WinSock2.h>
#pragma comment(lib, "ws2_32.lib")

char * GetLocalHostName()
{
	WSADATA wsaData;
	HOSTENT *pHost;
	char szHostName[256];

	if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
		exit(0);

	if (gethostname(szHostName, 256) == 0)
	{
		char *Host;
		Host = (char *)malloc(1024);
		pHost = gethostbyname(szHostName);
		strcpy(Host, pHost->h_name);
		return Host;
	}
	return "";
}

char * GetLocalHostAddr(int Count)
{
	WSADATA wsaData;
	HOSTENT *pHost;
	char szHostName[256];

	if (WSAStartup(MAKEWORD(2, 2), &wsaData) != 0)
		exit(0);

	if (gethostname(szHostName, 256) == 0)
	{
		char tmp[15];
		char *Addr;
		pHost = gethostbyname(szHostName);
		int index = 0;

		for (; index < 10; index++)
		{
			if (pHost->h_addr_list[index] == NULL)
				break;
		}

		sprintf(tmp, "%d.%d.%d.%d",
			pHost->h_addr_list[0][0] & 0xff,
			pHost->h_addr_list[0][1] & 0xff,
			pHost->h_addr_list[0][2] & 0xff,
			pHost->h_addr_list[0][3] & 0xff);

		Addr = (char *)malloc(15);
		strcpy(Addr, tmp);
		return Addr;
	}
	return "";
}

int main(int argc, char *argv[])
{
	char *hostname = GetLocalHostName();
	printf("本机名字: %s \n", hostname);

	char *hostaddr = GetLocalHostAddr(0);
	printf("本机IP: %s \n", hostaddr);

	system("pause");
	return 0;
}