Tokenize

$1.$ Start the program

$2.$ Include the header files.

$3.$ Allocate memory for the variable by dynamic memory allocation function.

$4.$ Use the file accessing functions to read the file.

$5.$ Get the input file from the user.

$6.$ Separate all the file contents as tokens and match it with the functions.

$7.$ Define all the keywords in a separate file and name it as key.c

$8.$ Define all the operators in a separate file and name it as open.c

$9.$ Give the input program in a file and name it as input.c

$10.$ Finally print the output after recognizing all the tokens.

$11.$ Stop the program.

Program:

#include

#include

#include

#include

int main$()$

$\{$

FILE $*$fi$,*$fo$,*$fop$,*$fk;

int flag$=0,$i$=1$;

char c$,$t$,$a$[15],$ch$[15],$file$[20]$;

printf$("$

Enter the File Name:"$)$;

scanf$("\%$s$",$&file$)$;

fi$=$fopen$($file$,"$r$")$;

fo$=$fopen$("$inter$.$c$","$w$")$;

fop$=$fopen$("$oper$.$c$","$r$")$;

fk$=$fopen$("$key$.$c$","$r$")$;

c$=$getc$($fi$)$;

while$(!$feof$($fi$))$

$\{$

if$($isalpha$($c$)||$isdigit$($c$)||($c$==\text{'}[\text{'}||$c$==\text{'}]\text{'}||$c$==\text{'}.\text{'}==1))$

fputc$($c$,$fo$)$;

else

$\{$

if$($c$==\text{'}$

$\text{'})$

fprintf$($fo$,"\backslash$t$$\backslash$t$")$;

else fprintf$($fo$,"\backslash$t$\%$c$\backslash$t$",$c$)$;

$\}$

c$=$getc$($fi$)$;

$\}$

fclose$($fi$)$;

fclose$($fo$)$;

fi$=$fopen$("$inter$.$c$","$r$")$;

printf$("$

Lexical Analysis"$)$;

fscanf$($fi$,"\%$s$",$a$)$;

printf$("$

Line: $\%$d

$",$i$++)$;

while$(!$feof$($fi$))$

$\{$

if$($strcmp$($a$,"$$$")==0)$

$\{$

printf$("$

Line: $\%$d

$",$i$++)$;

fscanf$($fi$,"\%$s$",$a$)$;

$\}$

fscanf$($fop$,"\%$s$",$ch$)$;

while$(!$feof$($fop$))$

$\{$

if$($strcmp$($ch$,$a$)==0)$

$\{$

fscanf$($fop$,"\%$s$",$ch$)$;

printf$("\backslash$t$\backslash$t$\%$s$\backslash$t:$\backslash$t$\%$s

$",$a$,$ch$)$;

flag$=1$;

$\}$

fscanf$($fop$,"\%$s$",$ch$)$;

$\}$

rewind$($fop$)$;

fscanf$($fk$,"\%$s$",$ch$)$;

while$(!$feof$($fk$))$

$\{$

if$($strcmp$($ch$,$a$)==0)$

$\{$

fscanf$($fk$,"\%$k$",$ch$)$;

printf$("\backslash$t$\backslash$t$\%$s$\backslash$t:$\backslash$tKeyword

$",$a$)$;

flag$=1$;

$\}$

fscanf$($fk$,"\%$s$",$ch$)$;

$\}$

rewind$($fk$)$;

if$($flag$==0)$

$\{$

if$($isdigit$($a$[0]))$

printf$("\backslash$t$\backslash$t$\%$s$\backslash$t:$\backslash$tConstant

$",$a$)$;

else

printf$("\backslash$t$\backslash$t$\%$s$\backslash$t:$\backslash$tIdentifier

$",$a$)$;

$\}$

flag$=0$;

fscanf$($fi$,"\%$s$",$a$)$; $\}$

getch$()$;

$\}$

Input Files:

Oper.c

$($ openpara

$)$ closepara

$\{$ openbrace

$\}$ closebrace

$<$ lesser

$>$ greater

$"$ doublequote

$\text{'}$ singlequote

: colon

; semicolon

# preprocessor

$=$ equal

$==$ asign

$\%$ percentage

$^$ bitwise

& reference

$*$ star

$+$ add

$-$ sub

$\backslash$ backslash

$/$ slash

Key.C

int

void

main

char

if

for

while

else

printf

scanf

FILE

Include

stdio.h

conio.h

iostream.h

Input.c

#include

#include

void main$()$

$\{$

int a$=10,$b $,$ c;

a$=$b$*$c;

getch$()$;

$\}$

Lab Assignment:

Find and fix the Lexical analysis errors in the code.