diff --git a/src/fakultaet.c b/src/fakultaet.c
new file mode 100644
index 0000000..46d9f0f
--- /dev/null
+++ b/src/fakultaet.c
@@ -0,0 +1,25 @@
+#include "fakultaet.h"
+
+int berechneFakultaetInt(int zahl) {
+    if (zahl == 0 || zahl == 1) {
+        return 1;
+    } else {
+        int fakultaet = 1;
+        for (int i = 2; i <= zahl; ++i) {
+            fakultaet *= i;
+        }
+        return fakultaet;
+    }
+}
+
+int berechneFakultaetDouble(double zahl) {
+    if (zahl == 0 || zahl == 1) {
+        return 1;
+    } else {
+        double fakultaet = 1;
+        for (double i = 2; i <= zahl; ++i) {
+            fakultaet *= i;
+        }
+        return fakultaet;
+    }
+}
diff --git a/src/fakultaet.h b/src/fakultaet.h
new file mode 100644
index 0000000..c7f6460
--- /dev/null
+++ b/src/fakultaet.h
@@ -0,0 +1,13 @@
+//
+// Created by Justin Trausch on 06.02.2024.
+//
+
+#ifndef LINKES_TWIX_FAKULTAET_H
+#define LINKES_TWIX_FAKULTAET_H
+
+int fakultaetInt(int a, int b);
+
+double fakultaetDouble(double a, double b);
+
+
+#endif //LINKES_TWIX_FAKULTAET_H
diff --git a/test/test_fakultaet.c b/test/test_fakultaet.c
new file mode 100644
index 0000000..7db2fd4
--- /dev/null
+++ b/test/test_fakultaet.c
@@ -0,0 +1,33 @@
+#ifdef TEST
+
+#include "unity.h"
+
+#include "fakultaet.h"
+#include "fakultaet.c"
+
+void setUp(void)
+{
+}
+
+void tearDown(void)
+{
+}
+
+void test_fakultaet_1(void)
+{
+    int result, expected = 24;
+
+    result = berechneFakultaetInt(4);
+
+    TEST_ASSERT_EQUAL_INT(expected, result);
+}
+
+void test_fakultaet_2(void)
+{
+    double result, expected = 24.0;
+
+    result = berechneFakultaetInt(4.0);
+
+    TEST_ASSERT_EQUAL_DOUBLE(expected, result);
+}
+#endif //TEST
\ No newline at end of file