如何从 LIBPCAP 获取信息?

我需要获取有关互联网包的信息，我正在尝试使用以下代码，但我没有C++经验。

我从本教程中执行了此代码 http://yuba.stanford.edu/~casado/pcap/section1.html

#include <stdio.h>
#include <stdlib.h>
#include <pcap.h>  /* GIMME a libpcap plz! */
#include <errno.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
int main(int argc, char **argv)
{
char *dev; /* name of the device to use */ 
char *net; /* dot notation of the network address */
char *mask;/* dot notation of the network mask    */
int ret;   /* return code */
char errbuf[PCAP_ERRBUF_SIZE];
bpf_u_int32 netp; /* ip          */
bpf_u_int32 maskp;/* subnet mask */
struct in_addr addr;
/* ask pcap to find a valid device for use to sniff on */
dev = pcap_lookupdev(errbuf);
/* error checking */
if(dev == NULL)
{
printf("%sn",errbuf);
exit(1);
}
/* print out device name */
printf("DEV: %sn",dev);
/* ask pcap for the network address and mask of the device */
ret = pcap_lookupnet(dev,&netp,&maskp,errbuf);
if(ret == -1)
{
printf("%sn",errbuf);
exit(1);
}
/* get the network address in a human readable form */
addr.s_addr = netp;
net = inet_ntoa(addr);
if(net == NULL)/* thanks Scott :-P */
{
perror("inet_ntoa");
exit(1);
}
printf("NET: %sn",net);
/* do the same as above for the device's mask */
addr.s_addr = maskp;
mask = inet_ntoa(addr);
if(mask == NULL)
{
perror("inet_ntoa");
exit(1);
}
printf("MASK: %sn",mask);
return 0;
}

当我执行此代码时，我得到一个文件a.out但我无法打开该文件，为什么？如何将我的信息传递给.csv？