#include <stdio.h>#include <netdb.h>   int  main(){	int i=0;    struct servent *ser;    while( ser=getservent())    { if (i>20) break;i++;       printf("name : %s  ",ser->s_name);       printf("port : %d  ",ntohs(ser->s_port));       printf("protocol:%s  ",ser->s_proto);       printf("alias: %s\n",ser->s_aliases[0]);    }}