关于TCP、IP的编成，UNIX，#include <sys/types.h>
#include <pwd.h>
#include "ourhdr.h"
int
main(void) /* 44BSD version */
{
struct passwd *ptr;
if ( (ptr = getpwnam("stevens")) == NULL)
err_sys("getpwnam error");
printf("pw_passwd = %s\n",
ptr->pw_passwd == NULL || ptr->pw_passwd[0] == 0 ?
"(null)" : ptr->pw_passwd);
exit(0);
}
