diff --git a/labs/04/Lexical_Analyzer.l b/labs/04/Lexical_Analyzer.l
new file mode 100644
index 0000000..6464ea5
--- /dev/null
+++ b/labs/04/Lexical_Analyzer.l
@@ -0,0 +1,33 @@
+%{
+#include <stdio.h>
+%}
+
+%%
+"//".                       printf("COMMENT\n ");
+"f"                         printf("floatdcl ");
+"i"                         printf("intdcl ");
+[a-zA-Z]+                   printf("id\n");
+[1-9][0-9]*\.[0-9]+         printf("fnum\n");
+[1-9][0-9]*                 printf("inum\n");
+"p"                         printf("print ");
+"-"                         printf("minus ");
+"="                         printf("assign ");
+"+"                         printf("plus ");
+"/"                         print("divide " )
+"*"                         print ("multiply ")
+[ \t\n]+			{ /* empty spaces */ }
+.					{ printf("UNKOWN CHAR '%s'\n", yytext); }
+%%
+
+int main(int argc, char **argv) {
+	if(argc > 1) {
+		FILE *file = fopen(argv[1], "r");
+		if(!file) {
+			perror("[!] Couldnt open file");
+			return 1;
+		}
+		yyin = file;
+	}
+	yylex();
+	return 0;
+}
\ No newline at end of file