diff --git a/labs/04/ac-lexical-analyzer-main/Makefile b/labs/04/ac-lexical-analyzer-main/Makefile
new file mode 100644
index 0000000..da6d6d8
--- /dev/null
+++ b/labs/04/ac-lexical-analyzer-main/Makefile
@@ -0,0 +1,28 @@
+# Makefile for the 'ac' lexical analyzer
+
+CC=gcc
+LEX=lex
+LEXFLAGS=
+OUT=lex_analaizer
+
+all: $(OUT)
+
+$(OUT): lex_analaizer.l
+	$(LEX) lex_analaizer.l
+	$(CC) lex.yy.c -o $(OUT)
+
+run: $(OUT)
+	@python code_generator.py > example.ac
+	@echo '=== INPUT (example.ac) ==='
+	@cat example.ac
+	@echo '\n=== OUTPUT (Tokens) ==='
+	@./$(OUT) example.ac
+
+clean:
+	rm -f lex.yy.c $(OUT) example.ac
+
+testcase:
+	@echo '=== INPUT (test_case.ac) ==='
+	@cat test_case.ac
+	@echo '\n=== OUTPUT (Tokens) ==='
+	@./lex_analaizer test_case.ac
diff --git a/labs/04/ac-lexical-analyzer-main/README.md b/labs/04/ac-lexical-analyzer-main/README.md
new file mode 100644
index 0000000..e82328d
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+++ b/labs/04/ac-lexical-analyzer-main/README.md
@@ -0,0 +1,54 @@
+# AC Lexical Analyzer
+
+This project contains a lexical analyzer for the "ac" programming language, implemented using Lex.
+
+## 📚 Language Description
+
+The language has the following lexical rules:
+- `f` → float declaration → `floatdcl`
+- `i` → int declaration → `intdcl`
+- `p` → print statement → `print`
+- Identifiers are single lowercase letters except `f`, `i`, and `p` → `id`
+- Integers → one or more digits → `inum`
+- Floats → digits followed by a dot and 1 to 5 digits → `fnum`
+- `=` → assignment → `assign`
+- `+` → addition → `plus`
+- Lines starting with `//` → `COMMENT`
+
+## 🛠️ How to Compile and Run
+
+1. Compile the scanner:
+```
+make
+```
+
+2. Run using the provided code generator:
+```
+make run
+```
+
+3. Clean all generated files:
+```
+make clean
+```
+
+## 🧰 Makefile Commands
+You can use the following commands from the terminal:
+
+- `make` → Compile the lexical analyzer from `lex_analaizer.l`
+- `make run` → Generate random input using `code_generator.py`, print it, and show the corresponding tokens
+- `make testcase` → Use the provided `test_case.ac` file, show it as input, and display the resulting tokens
+- `make clean` → Delete generated files (binary, test inputs, etc.)
+
+## 📁 File Structure
+### Existing Source Files:
+- `lex_analaizer.l` → Lexical analyzer definition
+- `Makefile` → Build and test automation
+- `code_generator.py` → Script to generate random AC language code
+- `test_case.ac` → A static test case used for validation
+- `README.md` → This documentation
+
+### Generated Files:
+- `lex.yy.c` → C code generated by `lex`
+- `lex_analaizer` → Compiled executable from `gcc`
+- `example.ac` → Random input file generated by `make run`
diff --git a/labs/04/ac-lexical-analyzer-main/code_generator.py b/labs/04/ac-lexical-analyzer-main/code_generator.py
new file mode 100644
index 0000000..4ae97e1
--- /dev/null
+++ b/labs/04/ac-lexical-analyzer-main/code_generator.py
@@ -0,0 +1,78 @@
+import string
+import random
+import argparse
+
+def id_generator(size=10, chars=string.ascii_uppercase + string.digits):
+    return ''.join(random.choice(chars) for _ in range(size))
+
+opreators = ["+","-","*","/"]
+
+def get_comment_line():
+    comment_line = "//%s" % (id_generator())
+    return comment_line
+
+def get_float_line():
+    float_line = "f %s" % (random.choice(string.ascii_lowercase))
+    return float_line
+
+def get_integer_line():
+    integer_line = "i %s"% (random.choice(string.ascii_lowercase))
+    return integer_line
+
+def get_asigment_line():
+    asigment_line = "%s = %s" %(random.choice(string.ascii_lowercase),\
+        random.randint(0,100))
+    return asigment_line
+
+def get_asigment_line_2():
+    asigment_line_2 = "%s = %s %s %s" % \
+            (random.choice(string.ascii_lowercase),\
+            random.choice(string.ascii_lowercase),\
+            random.choice(opreators),\
+            random.randint(0,100))
+    return asigment_line_2
+
+def get_print_line():
+    print_line = "p %s" % (random.choice(string.ascii_lowercase))
+    return print_line
+
+
+parser = argparse.ArgumentParser(description='Generate random AC code')
+parser.add_argument('--stress', dest='stress', action='store_true',\
+        help='generate HUGE code to stress the lab')
+args = parser.parse_args()
+
+if args.stress:
+    f= open("random_code.ac","w+")
+    for x in range(0, 100000):
+        comment_line = get_comment_line()
+        float_line = get_float_line()
+        integer_line = get_integer_line()
+        asigment_line = get_asigment_line()
+        asigment_line_2 = get_asigment_line_2()
+        print_line = get_print_line()
+
+        f.write(comment_line + "\n")
+        f.write(float_line + "\n")
+        f.write(integer_line + "\n")
+        f.write(asigment_line+ "\n")
+        f.write(asigment_line_2 + "\n")
+        f.write(print_line + "\n")
+
+    f.close()
+
+else:
+    comment_line = get_comment_line()
+    float_line = get_float_line()
+    integer_line = get_integer_line()
+    asigment_line = get_asigment_line()
+    asigment_line_2 = get_asigment_line_2()
+    print_line = get_print_line()
+
+    print(comment_line)
+    print(float_line)
+    print(integer_line)
+    print(asigment_line)
+    print(asigment_line_2)
+    print(print_line)
+
diff --git a/labs/04/ac-lexical-analyzer-main/lex_analaizer.l b/labs/04/ac-lexical-analyzer-main/lex_analaizer.l
new file mode 100644
index 0000000..b63ea5a
--- /dev/null
+++ b/labs/04/ac-lexical-analyzer-main/lex_analaizer.l
@@ -0,0 +1,42 @@
+%{
+#include <stdio.h>
+#include <string.h>
+
+extern FILE *yyin;
+%}
+
+/* Definitions */
+ID      [a-eg-hj-oq-z]
+DIGIT   [0-9]
+INT     {DIGIT}+
+FLOAT   {DIGIT}+"."{DIGIT}{1,5}
+
+%%
+"//".*                  { printf("COMMENT\n"); }
+"f"                     { printf("floatdcl\n"); }
+"i"                     { printf("intdcl\n"); }
+"p"                     { printf("print\n"); }
+"="                     { printf("assign\n"); }
+"+"                     { printf("plus\n"); }
+{FLOAT}                 { printf("fnum\n"); }
+{INT}                   { printf("inum\n"); }
+{ID}                    { printf("id\n"); }
+[ \t\r\n]+              { /* Ignore whitespace */ }
+.                       { printf("UNKNOWN TOKEN: %s\n", yytext); }
+%%
+
+int main(int argc, char **argv) {
+    if (argc > 1) {
+        yyin = fopen(argv[1], "r");
+        if (!yyin) {
+            perror("Error opening input file");
+            return 1;
+        }
+    }
+    yylex();
+    return 0;
+}
+
+int yywrap() {
+    return 1;
+}
diff --git a/labs/04/ac-lexical-analyzer-main/test_case.ac b/labs/04/ac-lexical-analyzer-main/test_case.ac
new file mode 100644
index 0000000..1d181b7
--- /dev/null
+++ b/labs/04/ac-lexical-analyzer-main/test_case.ac
@@ -0,0 +1,16 @@
+// basic code
+
+//float b
+f b
+
+// integer a
+i a
+
+// a = 5
+a = 5
+
+// b = a + 3.2
+b = a + 3.2
+
+//print 8.5
+p b