Lexical analysis is the process of reading in the stream of characters making up the source code of

a program and dividing the input into tokens. In this assignment, you will use regular expressions

and DFAs to implement a lexical analyzer for a subset of C programming language.

Your Task

Your task is to write a program that reads an input text file, and constructs a list of tokens in

that file. Your program may be written in C$,$ C$++,$ Java or any other programming language.

Assuming that the input file contains the following code string:

$2\mathrm{.}1$ Sample Input $($C$++$ code$)$

void main $()$

$\{$

int sum $=0$;

for$($int j$=0$; j $<mtext\; id="EditorElement\_922946"></mtext><mn\; id="EditorElement\_922947">1</mn><mn\; id="EditorElement\_922948">0</mn>$; j$=$j$+1)$

$\{$

sum $=$ sum $+$ j $+10\mathrm{.}43+34$E$4+45\mathrm{.}34$E$-4+$ E$43+\mathrm{.}34$;

$\}$

$\}$

$2\mathrm{.}2$ Sample Output

The output of the program should be similar to the following:

Class : Lexeme

keyword : void

identifier : main

Page

$2$

of $4$

Assignment $1($Lexical Analyzer$)$

Compiler Construction CS$4435($Spring $2015)$

University of Lahore

Maryam Bashir

Assigned: Saturday, March $14,2015.$ Due: Monday $23$rd March $201511$:$59$ PM

Lexical analysis

Lexical analysis is the process of reading in the stream of characters making up the source code of

a program and dividing the input into tokens. In this assignment, you will use regular expressions

and DFAs to implement a lexical analyzer for a subset of C programming language.

Your Task

Your task is to write a program that reads an input text file, and constructs a list of tokens in

that file. Your program may be written in C$,$ C$++,$ Java or any other programming language.

Assuming that the input file contains the following code string:

$2\mathrm{.}1$ Sample Input $($C$++$ code$)$

void main $()$

$\{$

int sum $=0$;

for$($int j$=0$; j $<mtext\; id="EditorElement\_923972"></mtext><mn\; id="EditorElement\_923973">1</mn><mn\; id="EditorElement\_923974">0</mn>$; j$=$j$+1)$

$\{$

sum $=$ sum $+$ j $+10\mathrm{.}43+34$E$4+45\mathrm{.}34$E$-4+$ E$43+\mathrm{.}34$;

$\}$

$\}$

$2\mathrm{.}2$ Sample Output

The output of the program should be similar to the following:

Class : Lexeme

keyword : void

identifier : main

$1$

$($Copyrighted by University of Lahore$)$

$($ : $($

$)$ : $)$

$\{$ : $\{$

keyword : int

identifier : sum

$=$ : $=$

num : $0$

; : ;

keyword : for

$($ : $($

keyword : int

identifier : j

$=$ : $=$

num : $0$

; : ;

identifier : j

$$ : $$

num : $10$

; : ;

identifier : j

$=$ : $=$

identifier : j

$+$ : $+$

num : $1$

$)$ : $)$

$\{$ : $\{$

identifier : sum

$=$ : $=$

identifier : sum

$+$ : $+$

identifier : j

$+$ : $+$

num : $10\mathrm{.}43$

$+$ : $+$

num : $34.$E$4$

$+$ : $+$

num : $45\mathrm{.}34$E$-4$

$+$ : $+$

identifier : E$43$

$+$ : $+$

Error : $.$

num : $34$

; : ;

$\}$ : $\}$

$\}$ : $\}$