请强人指点
#include " stdio.h"

#include " stdlib.h"

#include "Winsock2.h"

#include " iphelpapi.h"

Typedef DWORD (CALLBACK*PSARP) (

IPAddr DestIP, / /目的主机IP地址

IPAddr SrcIP, / / 源主机IP地址

PULONG pMacAddr, / / 返回的MAC地址

PULONG PhyAddrLen, / / 返回MAC地址的长度

addr) ; / /定义结构体

void main ( int argc, char**argv )

{

PSARP pSARP ;

HINSTANCE hInst; / /实例句柄

hInst =LoadLibrary( " iphelpapi.dll" ) ; / /加载IP Helper API所需的库文件

pSARP = ( PSARP) GetProcAddress ( hInst, " SendARP" ) ; / /获取SendARP函数的地址

/ /处理命令行参数

if ( argc ! = 2 )

{

printf ( " Get aMacAddress from host in a segment! \n" ) ;

printf ( "Usage: \n \GetMac. exe [Host IP] \n \n" ) ;

printf ( " Example: \n \GetMac. exe 192. 168. 0. 1 \n \n" ) ;

exit (0) ;

}

printf ( " \n IpAddress: % s\n" , argv[ 1 ] ) ;

int nRemoteAddr = inet_addr( argv[ 1 ] ) ; / /发送ARP查询包获得远程MAC地址

unsigned charmacAddress[ 6 ];

PULONG macAddLen = 6;

int iRet = pSARP ( nRemoteAddr,NULL, ( PULONG) &macAddress, &macAddLen) ;

if ( iRet = =NO_ERROR)

{

printf ( "MacAddress: " ) ;

for ( int i = 0; i < 6; i + + ) / /格式化输出获取的MAC地址

{

printf ( " %. 2x" ,macAddress[ i ] ) ;

if ( i < 5) p rintf ( " - " ) ;

}

}

else

printf ( " SendARP Error: % d \n" , GetLastError( ) ) ;

printf ( " \n" ) ;

}