#include "apue.h"#define	TOK_ADD	   5void	do_line(char *);void	cmd_add(void);int		get_token(void);intmain(void){	char	line[MAXLINE];	while (fgets(line, MAXLINE, stdin) != NULL)		do_line(line);	exit(0);}char	*tok_ptr;		/* global pointer for get_token() */voiddo_line(char *ptr)		/* process one line of input */{	int		cmd;	tok_ptr = ptr;	while ((cmd = get_token()) > 0) {		switch (cmd) {	/* one case for each command */		case TOK_ADD:				cmd_add();				break;		}	}}voidcmd_add(void){	int		token;	token = get_token();	/* rest of processing for this command */}intget_token(void){	/* fetch next token from line pointed to by tok_ptr */}