diff --git a/labs/04/lexico_scan.l b/labs/04/lexico_scan.l
new file mode 100644
index 0000000..93ea1bb
--- /dev/null
+++ b/labs/04/lexico_scan.l
@@ -0,0 +1,31 @@
+%{
+#include <stdio.h>
+%}
+
+%option noyywrap
+
+letter		[A-Za-z]
+integer		[0-9]+
+float		(0|[1-9][0-9]*)\.([0-9]*[1-9]|0)
+comment		\/\/.*
+id			{letter}({letter}|[0-9])*
+
+%%
+^p          {printf("print ");}
+^f			{printf("floatdcl ");}
+^i			{printf("intdcl ");}
+{id}		{printf("id ");}
+{integer}	{printf("inum ");}
+{float}		{printf("fnum ");}
+{comment}	{printf("COMMENT ");}
+\*			{printf("multiply ");}
+\=			{printf("assign ");}
+\-			{printf("minus ");}
+\+			{printf("sum ");}
+\/			{printf("div ");}
+%%
+
+int main(){
+	yylex();
+	return 0;
+}
\ No newline at end of file