读取命令、确定命令、执行命令的框架【学习笔记】

 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 int
10 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 void
22 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 void
37 cmd_add(void)