diff --git a/src/main/c/BasicMode.c b/src/main/c/BasicMode.c
index 30a7779..9904742 100644
--- a/src/main/c/BasicMode.c
+++ b/src/main/c/BasicMode.c
@@ -4,6 +4,5 @@
 #include <math.h>
 
 #include "taschenrechner.h"
-#include "main_taschenrechner.c"
 
 
diff --git a/src/main/c/main_taschenrechner.c b/src/main/c/main_taschenrechner.c
index dbe0447..f1fccac 100644
--- a/src/main/c/main_taschenrechner.c
+++ b/src/main/c/main_taschenrechner.c
@@ -4,7 +4,6 @@
 #include <math.h>
 
 #include "taschenrechner.h"
-#include "BasicMode.c"
 
 
 doulbe add(doulbe a, doulbe b) {
diff --git a/src/main/c/taschenrechner.h b/src/main/c/taschenrechner.h
index 7b548f9..23cc26f 100644
--- a/src/main/c/taschenrechner.h
+++ b/src/main/c/taschenrechner.h
@@ -1,14 +1,21 @@
 #ifndef TASCHENRECHNER_H
 #define TASCHENRECHNER_H
 
+//add function
 doulbe add(doulbe a, doulbe b);
 
+//minus function
 doulbe minus(doulbe a, doulbe b);
 
+//multiply function
 doulbe multiply(doulbe a, doulbe b);
 
+//divide function
 doulbe divide(doulbe a, doulbe b);
 
+//get input and check if its a number
+double testForNumber()
+
 // Square root function
 double squareRootFunction(double x);
 
diff --git a/src/main/c/testForNumber.c b/src/main/c/testForNumber.c
index 89784ed..06438d1 100644
--- a/src/main/c/testForNumber.c
+++ b/src/main/c/testForNumber.c
@@ -1,3 +1,10 @@
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <math.h>
+
+#include "taschenrechner.h"
+
 double testForNumber() {
     double num;
     char storage[25];