diff --git a/src/parser/lexical_analyzer.l b/src/parser/lexical_analyzer.l
index 18b2b893ceee611e94ba053df6742f813031fa45..b13f2824743692371ce75d0f4fc965709c0c99ae 100755
--- a/src/parser/lexical_analyzer.l
+++ b/src/parser/lexical_analyzer.l
@@ -18,9 +18,90 @@ void pass_node(char *text){
 
 /***************
  TO STUDENTS: Copy your Lab1 here. Make adjustments if necessary.
+ADD		\+ 
+SUB		\- 
+MUL		\*
+DIV 	\/ 
+LT 		\< 
+LTE 	\<\= 
+GT 		\>
+GTE 	\>\=
+EQ 		\=\= 
+NEQ 	\!\=
+ASSIN 	\= 
+SEMICOLON 	\; 
+COMMA 		\, 
+LPARENTHESE \( 
+RPARENTHESE \) 
+LBRACKET 	\[ 
+RBRACKET 	\] 
+LBRACE 		\{ 
+RBRACE 		\} 
+ELSE 	else 
+IF 		if 
+INT 	int 
+FLOAT 	float 
+RETURN 	return 
+VOID 	void 
+WHILE 	while 
+
+IDENTIFIER 	[a-zA-Z]+
+INTEGER 	[0-9]+
+FLOATPOINT 	[0-9]+\.|[0-9]*\.[0-9]+
+ARRAY 		\[\] 
+
+EOL 		[\n]
+COMMENT 	\/\*([^\*]|(\*)*[^\*\/])*(\*)*\*\/
+BLANK 		[ \f\n\r\t\v]
+ERROR 		.
+TAB         [\t]+
 
  Note: don't modify the prologue unless you know what you are doing.
 ***************/
 
 /* Example for you :-) */
-\+  { pos_start = pos_end; pos_end += 1; pass_node(yytext); return ADD; }
+\+ {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext);return ADD;}
+\- {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext);return SUB;}
+\* {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext);return MUL;}
+\/ {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext);return DIV;}
+\< {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return LT;}
+\<\= {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return LTE;}
+\> {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return GT;}
+\>\= {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return EQ;}
+\!\= {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return NEQ;}
+\= {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return ASSIN;}
+
+\; {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return SEMICOLON;}
+\, {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return COMMA;}
+\( {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return LPARENTHESE;}
+\) {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return RPARENTHESE;}
+\[ {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return LBRACKET;}
+\] {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return RBRACKET;}
+\{ {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return LBRACE;}
+\} {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return RBRACE;}
+
+else {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return ELSE;}
+if {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return IF;}
+int {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return INT;}
+float {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return FLOAT;}
+return {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return RETURN;}
+void {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return VOID;}
+while {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return WHILE;}
+
+[a-zA-Z]+ {pos_start = pos_end; pos_end += strlen(yytext); return IDENTIFIER;} 
+[0-9]+ {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return INTEGER;} 
+[0-9]+\.|[0-9]*\.[0-9]+ {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return FLOATPOINT;}
+\[\] {pos_start = pos_end; pos_end += strlen(yytext); pass_node(yytext); return ARRAY;}
+
+[\t]+ {pos_start=pos_end;pos_end+=strlen(yytext);}
+\/\*([^\*]|(\*)*[^\*\/])*(\*)*\*\/ {
+    for (int i=0;i<strlen(yytext);i++)
+    {
+        if(yytext[i]=='\n'){pos_start=1;pos_end=1;lines++;}
+        else pos_end++;
+    }
+}
+[\n] {pos_start=1;pos_end=1;lines+=strlen(yytext);} 
+[ \f\n\r\t\v] {pos_start=pos_end;pos_end+=strlen(yytext);}
+
+. {printf("error\n");}
\ No newline at end of file