diff --git a/bintree.c b/bintree.c
index 1201de5..a5bc809 100644
--- a/bintree.c
+++ b/bintree.c
@@ -65,7 +65,7 @@ void *nextTreeData(TreeNode *root)
     static StackNode *stack = NULL;
     static TreeNode* currentNode = NULL;
     void* result;
-
+    //erste initialisierung mit NULL
 	if(stack==NULL && root != NULL){
         currentNode = root;
 	 	while(currentNode != NULL){
diff --git a/bintreeTests.c b/bintreeTests.c
index 21efac5..701dd62 100644
--- a/bintreeTests.c
+++ b/bintreeTests.c
@@ -6,7 +6,8 @@ void setUp(void){}
 void tearDown(void){}
 
 void TEST_BINTREE(){
-    int input[8]={1,2,3,4,5,6,7,8};
+    int input[8]={7,3,2,4,8,6,1,5};
+    int expected[8]={1,2,3,4,5,6,7,8};
     int output[8];
     int len = 8;
     TreeNode* root = NULL;
@@ -21,7 +22,7 @@ void TEST_BINTREE(){
 
     }
 
-    TEST_ASSERT_INT_ARRAY_WITHIN(0, input, output, 8);
+    TEST_ASSERT_INT_ARRAY_WITHIN(0, expected, output, 8);
 
 }
 
diff --git a/numbers.c b/numbers.c
index 5074138..3403117 100644
--- a/numbers.c
+++ b/numbers.c
@@ -14,7 +14,7 @@
 // Returns len random numbers between 1 and 2x len in random order which are all different, except for two entries.
 // Returns NULL on errors. Use your implementation of the binary search tree to check for possible duplicates while
 // creating random numbers.
-unsigned int *createNumbers(unsigned int len)
+unsigned int* createNumbers(unsigned int len)
 {
 	srand(time(NULL));
 	unsigned int* numbers =malloc(sizeof(unsigned int) * len);
@@ -26,7 +26,7 @@ unsigned int *createNumbers(unsigned int len)
 
     if(numbers == NULL)return NULL;
 
-
+    //array mit verschiedenen zufallszahlen befüllen
 	while(generated<len){
 
 		numberTemp = (rand() % (2*len))+1;
@@ -42,7 +42,7 @@ unsigned int *createNumbers(unsigned int len)
 		}
 	}
 
-
+    //Duplikat erstellen
 	int DuplicateId;
 	int DuplicatePlace;
 
diff --git a/stack.c b/stack.c
index be0f396..9d1f5a6 100644
--- a/stack.c
+++ b/stack.c
@@ -8,7 +8,7 @@
     * `clearStack`: gibt den gesamten Speicher frei. */
 
 // Pushes data as pointer onto the stack.
-StackNode *push(StackNode *stack, void *data)
+StackNode *push(StackNode *stack, void *data)      //Neuer Knoten wird oben auf den Stack gelegt
 {
 	StackNode* stacknew = malloc(sizeof(StackNode));
 
@@ -20,7 +20,7 @@ StackNode *push(StackNode *stack, void *data)
 
 // Deletes the top element of the stack (latest added element) and releases its memory. (Pointer to data has to be
 // freed by caller.)
-StackNode *pop(StackNode *stack)
+StackNode *pop(StackNode *stack)        //Oberster Knoten wird gelöscht, der darunter wird zurückgegeben
 {
 	StackNode *ptr = stack->prev;
 
@@ -29,7 +29,7 @@ StackNode *pop(StackNode *stack)
 }
 
 // Returns the data of the top element.
-void *top(StackNode *stack)
+void *top(StackNode *stack)      //Daten des obersten Knoten werden ausgelesen
 {
 
     return stack->value;
@@ -37,7 +37,7 @@ void *top(StackNode *stack)
 }
 
 // Clears stack and releases all memory.
-void clearStack(StackNode *stack)
+void clearStack(StackNode *stack)       //gesamter Stack wird gefereed
 {
     StackNode *ptr = stack;
 
diff --git a/timer.c b/timer.c
index fd8f6c1..3e13691 100644
--- a/timer.c
+++ b/timer.c
@@ -1,6 +1,10 @@
+#define _POSIX_C_SOURCE 199309L
 #include "timer.h"
 
-#if __APPLE__
+#include <stdio.h>
+#include <time.h>
+
+/*#if __APPLE__
 #include <sys/time.h>
 static struct timespec start = {0, 0};
 
@@ -38,18 +42,55 @@ static clock_t startClocks = 0;
 void startTimer()
 {
     startClocks = clock();
+
+    printf("\nstartclocks: %ld\n", startClocks);
 }
 
 // Returns the time in seconds since startTimer() was called.
 double stopTimer()
 {
-    double measuredSeconds = (clock() - (double)startClocks) / CLOCKS_PER_SEC;
+    clock_t endClocks = clock();
 
+    printf("\nendclocks: %ld\n", endClocks);
+    printf("\ndeltatimer: %ld\n", (endClocks - startClocks));
+
+    printf("CLOCKS_PER_SECONDS: %ld\n", CLOCKS_PER_SEC);
+    double measuredSeconds = (double)(endClocks - startClocks) / CLOCKS_PER_SEC;
     if(startClocks > 0)
         startClocks = 0;
     else
         measuredSeconds = -1;
 
+    printf("measuredsecondes: %f\n", measuredSeconds);
+
     return measuredSeconds;
 }
-#endif
\ No newline at end of file
+
+
+
+#endif*/
+
+static struct timespec start;
+
+void startTimer() {
+
+    clock_gettime(CLOCK_MONOTONIC, &start);
+}
+
+static struct timespec end;
+double stopTimer() {
+
+    clock_gettime(CLOCK_MONOTONIC, &end);
+
+    double measuredseconds = (double)(end.tv_sec - start.tv_sec) + (double)(end.tv_nsec - start.tv_nsec) * 0.000000001;
+    if (start.tv_sec>0 || start.tv_nsec>0){
+        end.tv_nsec = 0;
+        end.tv_sec  =0;
+        start.tv_sec  = 0;
+        start.tv_nsec = 0;
+    }else {
+        measuredseconds = -1;
+    }
+
+    return measuredseconds;
+}
diff --git a/timer.h b/timer.h
index 180f8ac..2e46177 100644
--- a/timer.h
+++ b/timer.h
@@ -1,6 +1,6 @@
 #ifndef TIMER_H
 #define TIMER_H
-
+#include <time.h>
 // Usage of time.h: clock() returns the number of clock ticks since program start. CLOCKS_PER_SECONDS represents the
 // number of clock ticks per second.
 
@@ -10,4 +10,8 @@ void startTimer();
 // Returns the time in seconds since startTimer() was called.
 double stopTimer();
 
+struct timespec {
+    time_t tv_sec;
+    long   tv_nsec;
+};
 #endif