- 4


,

token ,

token_type DELIMITER.

.

.

, , ,

. look_up()

, ,

,

().  

ꠠ . , ,

, ,

. token

.

get_token() , :

PRINT A+100-(B*C)/2

--------------------------------

ࠠ .

PRINT COMMAND

A VARIABLE

+ DELIMITER

100 NUMBER

- DELIMITER

( DELIMITER

B VARIABLE

* DELIMITER

C VARIABLE

) DELIMITER

/ DELIMITER

2 NUMBER

null DELIMITER

, token , .

. . putback() .

/* */

void putback()

char *t;

t = token;

for(; *t; t++) prog--;