1 #include "apue.h" 2  3 #define TOK_ADD    5 4  5 void    do_line(char *); 6 void    cmd_add(void); 7 int     get_token(void); 8  9 int10 main(void)11 {12     char    line[MAXLINE];13 14     while (fgets(line, MAXLINE, stdin) != NULL)15         do_line(line);16     exit(0);17 }18 19 char    *tok_ptr;       /* global pointer for get_token() */20 21 void22 do_line(char *ptr)      /* process one line of input */23 {24     int     cmd;25 26     tok_ptr = ptr;27     while ((cmd = get_token()) > 0) {28         switch (cmd) {  /* one case for each command */29         case TOK_ADD:30                 cmd_add();31                 break;32         }33     }34 }35 36 void37 cmd_add(void)