more stack tests and fix in stack

Reviewed-on: #1

bintree.c

@@ -1,155 +1,117 @@
 #include <string.h>
+#include <stdlib.h>
 #include "stack.h"
 #include "bintree.h"
-#include <stdlib.h>
 
-// TODO: binären Suchbaum implementieren
+static StackNode *iterStack = NULL;
-/*  * `addToTree`: fügt ein neues Element in den Baum ein (rekursiv),
+static void pushLeftBranch(StackNode **stack, TreeNode *node);
- * `clearTree`: gibt den gesamten Baum frei (rekursiv),
- * `treeSize`: zählt die Knoten im Baum (rekursiv),
- * `nextTreeData`: Traversierung mit Hilfe des zuvor implementierten Stacks. */
 
-// Adds a copy of data's pointer destination to the tree using compareFct for ordering. Accepts duplicates
+// Inserts a new node into the BST.
-// if isDuplicate is NULL, otherwise ignores duplicates and sets isDuplicate to 1 (or to 0 if a new entry is added).
+// If isDuplicate == NULL → duplicates are allowed
-TreeNode *addToTree(TreeNode *root, const void *data, size_t dataSize, CompareFctType compareFct, int *isDuplicate)
+// If isDuplicate != NULL → duplicates are ignored and *isDuplicate = 1
+TreeNode *addToTree(TreeNode *root, const void *data, size_t dataSize,
+                    CompareFctType compareFct, int *isDuplicate)
 {
-    TreeNode *insertedNode;
-
-    // create a new node if the current node is NULL
     if (root == NULL)
     {
-        // it's important to zero the pointers for adjacent nodes
+        TreeNode *newNode = calloc(1, sizeof(TreeNode));
-        insertedNode = calloc(1, sizeof(TreeNode));
+        if (!newNode)
-        if (!insertedNode)
+            return NULL;
+
+        newNode->data = malloc(dataSize);
+        if (!newNode->data)
         {
+            free(newNode);
             return NULL;
         }
 
-        insertedNode->data = malloc(dataSize);
+        memcpy(newNode->data, data, dataSize);
-        if (!insertedNode->data)
+
-        {
-            return NULL;
-        }
-        memcpy(insertedNode->data, data, dataSize);
-        // reset isDuplicate if it exists
         if (isDuplicate)
-        {
             *isDuplicate = 0;
-        }
+
-        return insertedNode;
+        return newNode;
     }
 
-    // TODO: what is the correct data type here?
+    int cmp = compareFct(data, root->data);
-    int cmpRes = (*compareFct)(data, root->data);
+
-    // insert into the left branch
+    if (cmp < 0 || (cmp == 0 && isDuplicate == NULL))
-    if (cmpRes < 0 || (cmpRes == 0 && isDuplicate == NULL))
     {
         root->left = addToTree(root->left, data, dataSize, compareFct, isDuplicate);
     }
-    // insert into the right branch
+    else if (cmp > 0)
-    else if (cmpRes > 0)
     {
         root->right = addToTree(root->right, data, dataSize, compareFct, isDuplicate);
     }
-    // the data is equal to the current node
     else
     {
-        // the data already exists in the tree and duplicates are ignored (isDuplicate* not NULL)
+        if (isDuplicate)
             *isDuplicate = 1;
     }
+
     return root;
 }
 
-// push all left descendants from @param node
+static void pushLeftBranch(StackNode **stack, TreeNode *node)
-static void pushLeftDesc(StackNode **stackPtr, TreeNode *node)
 {
-    if (!stackPtr || !node)
+    while (node)
     {
-        return;
+        *stack = push(*stack, node);
-    }
+        node = node->left;
-    TreeNode *curNode = node;
-    while (curNode->left)
-    {
-        *stackPtr = push(*stackPtr, curNode->left);
-        if (!*stackPtr)
-        {
-            return;
-        }
-        curNode = curNode->left;
     }
 }
 
-// Iterates over the tree given by root. Follows the usage of strtok. If tree is NULL, the next entry of the last tree given is returned in ordering direction.
+// If root != NULL → reset iterator and start from new tree.
-// Use your implementation of a stack to organize the iterator. Push the root node and all left nodes first. On returning the next element,
+// If root == NULL → continue iterating.
-// push the top node and push all its left nodes.
 void *nextTreeData(TreeNode *root)
 {
-    // this creates a static variable that maintains an internal state
+    // Start new iteration
-    static StackNode *stack;
+    if (root != NULL)
+    {
+        // reset old iterator state
+        clearStack(iterStack);
+        iterStack = NULL;
 
-    // create a new stack
+        // push root and all left children
-    if (root)
+        pushLeftBranch(&iterStack, root);
-    {
+    }
-        // clear possibly existing stacks
+
-        clearStack(stack);
+    // No active iterator
-        // init a new stack
+    if (iterStack == NULL)
-        stack = push(NULL, root);
-        // init failed
-        if (!stack)
-        {
         return NULL;
-        }
-        pushLeftDesc(&stack, root);
 
-        // return the first val
+    // Get next node
-        return nextTreeData(NULL);
+    TreeNode *node = (TreeNode *)top(iterStack);
-    }
+    iterStack = pop(iterStack);
 
-    // neither stack nor root exist
+    // push right subtree and its left descendants
-    if (!stack)
+    if (node->right)
-    {
+        pushLeftBranch(&iterStack, node->right);
-        return NULL;
-    }
 
-    // get next val with stack
+    return node->data;
-    TreeNode *res = top(stack);
-    stack = pop(stack);
-    if (res->right)
-    {
-        stack = push(stack, res->right);
-        pushLeftDesc(&stack, res->right);
-    }
-
-    return res->data;
 }
 
-// Releases all memory resources (including data copies).
+// Frees all nodes and also resets iterator.
 void clearTree(TreeNode *root)
 {
-    // this check is crucial for recursion
     if (!root)
-    {
-        // nothing to clear
         return;
-    }
 
-    // release the resources of child nodes first
     clearTree(root->left);
     clearTree(root->right);
 
-    // free the data (it's just a copy created in addToTree())
     free(root->data);
     free(root);
+
+    // If we clear the tree, iterator must not point into freed memory.
+    clearStack(iterStack);
+    iterStack = NULL;
 }
 
-// Returns the number of entries in the tree given by root.
 unsigned int treeSize(const TreeNode *root)
 {
-    // there are no nodes
     if (!root)
-    {
         return 0;
-    }
 
     return 1 + treeSize(root->left) + treeSize(root->right);
 }

numbers.c

@@ -5,87 +5,79 @@
 #include "numbers.h"
 #include "bintree.h"
 
-static int compareInt(const void *ptr1, const void *ptr2);
+//Speicher für Array erstellen, zufällige Zahlen von 1-2xlen erzeugen, mittels Binärbaum checken, ob Zahlen einzigartig sind
+//Eine Zahl duplizieren, an zufälliger Stelle einfügen und die Zahl an der Stelle ans Ende schieben
+const int compare (const void *a, const void *b);
 
-// TODO: getDuplicate und createNumbers implementieren
-/*  *   * Erzeugen eines Arrays mit der vom Nutzer eingegebenen Anzahl an Zufallszahlen.
- * Sicherstellen, dass beim Befüllen keine Duplikate entstehen.
- * Duplizieren eines zufälligen Eintrags im Array.
- * in `getDuplicate()`: Sortieren des Arrays und Erkennen der doppelten Zahl durch Vergleich benachbarter Elemente. */
-
-// 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.
-
-/*
-the implemented tree can't efficiently check if it contains a specific number, but we don't actually need that anyways
-create numbers just counts and checks if the just inserted number sets the isDuplicate pointer
-*/
-// srand should have been called before this function
 unsigned int *createNumbers(unsigned int len)
 {
-  unsigned int *randomNumbers = malloc(len * sizeof(int));
+  unsigned int *numbers = malloc (sizeof(unsigned int) * len);
-
+  unsigned int upperLimit = len * 2;
-  if (!randomNumbers)
-  {
-    return NULL;
-  }
-
-  // including upper limit
-  int upperLimit = len * 2;
-
-  int numberCnt = 0;
-
   int isDuplicate = 0;
-  TreeNode *root = NULL;
+  TreeNode *binTree = NULL;
-  // we only need len-1 numbers because 1 will be duplicated
+
-  while (numberCnt < len - 1)
+  for (unsigned int i = 0; i < len; i++) {
+    do
     {
-    // numbers up to and including upperLimit without 0
-    int randNum = rand() % upperLimit + 1;
-    // reset isDuplicate
       isDuplicate = 0;
-    // don't forget to set the root here
+      numbers[i] = rand () % upperLimit + 1;
-    root = addToTree(root, &randNum, sizeof(randNum), (CompareFctType)compareInt, &isDuplicate);
+      binTree = addToTree(binTree, &numbers[i], sizeof(unsigned int), compare, &isDuplicate);
-    if (isDuplicate)
+    } while (isDuplicate);
-    {
-      // number already exists
-      continue;
-    }
-    randomNumbers[numberCnt++] = randNum;
   } 
 
-  // select which number to duplicate
+  unsigned int duplicate = numbers[rand () % len];
-  int dupNum = randomNumbers[rand() % numberCnt];
+  int indexDuplicate;
-  // ...and where to insert
-  int dupNumIdx = rand() % len;
 
-  // move the number currently at the dupNumIdx to the end
+  do {
-  // and insert the dupNum at the index
+    indexDuplicate = rand() % len;
-  // this also works if the last idx was selected for dupNum
+  } while (numbers[indexDuplicate] == duplicate);
-  randomNumbers[len - 1] = randomNumbers[dupNumIdx];
-  randomNumbers[dupNumIdx] = dupNum;
 
-  // clean up memory
+  if (numbers[len-1] != duplicate) {
-  clearTree(root);
+    numbers[len-1] = numbers[indexDuplicate];
-  return randomNumbers;
+  }
+  
+  numbers[indexDuplicate] = duplicate;
+  
+  clearTree(binTree);
+  
+  return numbers;
 }
 
-// Returns only the only number in numbers which is present twice. Returns zero on errors.
+//Vergleichsfunktion von qsort
+const int compare (const void *a, const void *b) {
+  const unsigned int *x = a;
+  const unsigned int *y = b;
+  if (*x < *y) {
+    return -1;
+  }
+  else if (*x > *y) {
+    return 1;
+  }
+  else {
+    return 0;
+  }
+}
+
+//Sortiert Zahlen mit qsort, vergleicht dann benachbarte Elemente und gibt bei Erfolg die doppelte Zahl zurück
 unsigned int getDuplicate(const unsigned int numbers[], unsigned int len)
 {
-  qsort((void *)numbers, len, sizeof(int), compareInt); // sort the array
+  if (len < 2) {
-  for (int i = 0; i < len - 1; i++)
+    return 0;
-  {
+  }
-    if (numbers[i] == numbers[i + 1])
+
-      return numbers[i];
+unsigned int *copy = malloc (sizeof(unsigned int) * len);
+memcpy (copy, numbers, sizeof(unsigned int) * len);
+
+qsort(copy, len, sizeof(unsigned int), compare);
+
+for (int i = 0; i < len-1; i++) {
+  if (copy[i] == copy [i+1]) {
+    unsigned int result = copy [i];
+    free (copy);
+    return result;
   }
-  return 0; // zero on errors
 }
 
-static int compareInt(const void *ptr1, const void *ptr2)
+free (copy);
-{
+return 0;
-  int num1 = *(int *)ptr1;
-  int num2 = *(int *)ptr2;
-  return num1 - num2;
 }

stack.c

@@ -50,6 +50,8 @@ void *top(StackNode *stack)
 // Clears stack and releases all memory.
 void clearStack(StackNode *stack)
 {
-    while (pop(stack))
+    while (stack)
-        ;
+    {
+        stack = pop(stack);
+    }
 }

test_bintree.c

@@ -1,39 +1,145 @@
 #include "unity.h"
 #include "bintree.h"
-#include "string.h"
+#include <string.h>
+#include <stdio.h>
+
+static int compareInt(const void *a, const void *b)
+{
+    int x = *(const int *)a;
+    int y = *(const int *)b;
+    return (x > y) - (x < y);
+}
 
 void setUp(void)
 {
-    // set stuff up here
 }
 
 void tearDown(void)
 {
-    // set stuff up here
 }
 
-// this adds some strings and checks if they are returned in the right order
+/* ============================================================
-void test_insert_and_retrieve(void)
+   TEST 1 — Strings einfügen + korrekte Reihenfolge prüfen
+   ============================================================ */
+
+void test_insert_and_retrieve_strings(void)
 {
     char *data1 = "a_this";
     char *data2 = "b_is";
     char *data3 = "c_testdata";
 
-    TreeNode *root = addToTree(NULL, data1, strlen(data1) + 1, (CompareFctType)&strcmp, NULL);
+    TreeNode *root = addToTree(NULL, data1, strlen(data1) + 1, (CompareFctType)strcmp, NULL);
-    addToTree(root, data2, strlen(data2) + 1, (CompareFctType)&strcmp, NULL);
+    addToTree(root, data2, strlen(data2) + 1, (CompareFctType)strcmp, NULL);
-    addToTree(root, data3, strlen(data3) + 1, (CompareFctType)&strcmp, NULL);
+    addToTree(root, data3, strlen(data3) + 1, (CompareFctType)strcmp, NULL);
 
-    TEST_ASSERT_EQUAL_STRING(data1, (char *)nextTreeData(root));
+    TEST_ASSERT_EQUAL_STRING(data1, nextTreeData(root));
-    TEST_ASSERT_EQUAL_STRING(data2, (char *)nextTreeData(NULL));
+    TEST_ASSERT_EQUAL_STRING(data2, nextTreeData(NULL));
-    TEST_ASSERT_EQUAL_STRING(data3, (char *)nextTreeData(NULL));
+    TEST_ASSERT_EQUAL_STRING(data3, nextTreeData(NULL));
+    TEST_ASSERT_EQUAL_PTR(NULL, nextTreeData(NULL)); // Ende
 
     clearTree(root);
 }
 
+/* ============================================================
+   TEST 2 — Integer einfügen + Traversierung
+   ============================================================ */
+
+void test_insert_and_retrieve_ints(void)
+{
+    int a = 2, b = 1, c = 3;
+
+    TreeNode *root = NULL;
+    root = addToTree(root, &a, sizeof(int), compareInt, NULL);
+    addToTree(root, &b, sizeof(int), compareInt, NULL);
+    addToTree(root, &c, sizeof(int), compareInt, NULL);
+
+    int *v1 = nextTreeData(root);
+    int *v2 = nextTreeData(NULL);
+    int *v3 = nextTreeData(NULL);
+    int *v4 = nextTreeData(NULL);
+
+    TEST_ASSERT_EQUAL_INT(1, *v1);
+    TEST_ASSERT_EQUAL_INT(2, *v2);
+    TEST_ASSERT_EQUAL_INT(3, *v3);
+    TEST_ASSERT_NULL(v4);
+
+    clearTree(root);
+}
+
+/* ============================================================
+   TEST 3 — treeSize korrekt?
+   ============================================================ */
+
+void test_tree_size(void)
+{
+    TreeNode *root = NULL;
+
+    TEST_ASSERT_EQUAL_UINT(0, treeSize(root));
+
+    int x1 = 10, x2 = 5, x3 = 15;
+    root = addToTree(root, &x1, sizeof(int), compareInt, NULL);
+    addToTree(root, &x2, sizeof(int), compareInt, NULL);
+    addToTree(root, &x3, sizeof(int), compareInt, NULL);
+
+    TEST_ASSERT_EQUAL_UINT(3, treeSize(root));
+
+    clearTree(root);
+}
+
+/* ============================================================
+   TEST 4 — Duplikaterkennung
+   ============================================================ */
+
+void test_duplicate_detection(void)
+{
+    int x = 42;
+    int dupFlag = -1;
+
+    TreeNode *root = addToTree(NULL, &x, sizeof(int), compareInt, &dupFlag);
+    TEST_ASSERT_EQUAL_INT(0, dupFlag);
+
+    addToTree(root, &x, sizeof(int), compareInt, &dupFlag);
+    TEST_ASSERT_EQUAL_INT(1, dupFlag);
+
+    TEST_ASSERT_EQUAL_UINT(1, treeSize(root));
+
+    clearTree(root);
+}
+
+/* ============================================================
+   TEST 5 — Iterator nach clearTree → sollte NULL liefern
+   ============================================================ */
+
+void test_iterator_after_cleartree(void)
+{
+    int a = 5, b = 1, c = 9;
+
+    TreeNode *root = NULL;
+    root = addToTree(root, &a, sizeof(int), compareInt, NULL);
+    addToTree(root, &b, sizeof(int), compareInt, NULL);
+    addToTree(root, &c, sizeof(int), compareInt, NULL);
+
+    nextTreeData(root);
+
+    clearTree(root);
+
+    TEST_ASSERT_NULL(nextTreeData(NULL));
+    TEST_ASSERT_NULL(nextTreeData(NULL));
+}
+
 int main(void)
 {
-    printf("============================\nBintree tests\n============================\n");
+    printf("============================\n");
+    printf("Bintree tests\n");
+    printf("============================\n");
+
     UNITY_BEGIN();
-    RUN_TEST(test_insert_and_retrieve);
+
+    RUN_TEST(test_insert_and_retrieve_strings);
+    RUN_TEST(test_insert_and_retrieve_ints);
+    RUN_TEST(test_tree_size);
+    RUN_TEST(test_duplicate_detection);
+    RUN_TEST(test_iterator_after_cleartree);
+
     return UNITY_END();
 }

test_numbers.c

@@ -1,8 +1,9 @@
 #include "unity.h"
-// #include "bintree.h"
-// #include "string.h"
 #include "numbers.h"
 #include "stdlib.h"
+#include "string.h"
+
+static int compareInt(const void *ptr1, const void *ptr2);
 
 void setUp(void)
 {
@@ -16,7 +17,7 @@ void tearDown(void)
 
 // getDuplicate on array without duplicats
 // expects 0/error
-void test_get_duplicate_error(void)
+void test_get_duplicate_without_duplicates(void)
 {
     unsigned int input[] = {1, 5, 9, 2, 4};
     unsigned int len = sizeof(input) / sizeof(input[0]);
@@ -24,6 +25,21 @@ void test_get_duplicate_error(void)
     TEST_ASSERT_EQUAL_UINT(0, getDuplicate(input, len));
 }
 
+// getDuplicate() on some arrays with 1 duplicate
+void test_get_duplicate(void)
+{
+    unsigned int arr1[] = {4, 15, 32, 5, 3, 8, 8};
+    unsigned int len1 = sizeof(arr1) / sizeof(arr1[0]);
+    unsigned int arr2[] = {1, 3, 3, 7};
+    unsigned int len2 = sizeof(arr2) / sizeof(arr2[0]);
+    unsigned int arr3[] = {7, 7, 8, 4, 9, 1};
+    unsigned int len3 = sizeof(arr3) / sizeof(arr3[0]);
+
+    TEST_ASSERT_EQUAL_UINT(8, getDuplicate(arr1, len1));
+    TEST_ASSERT_EQUAL_UINT(3, getDuplicate(arr2, len2));
+    TEST_ASSERT_EQUAL_UINT(7, getDuplicate(arr3, len3));
+}
+
 // this tries to brute force a triple
 void test_for_triple(void)
 {
@@ -33,18 +49,79 @@ void test_for_triple(void)
         unsigned int *numbers = createNumbers(3);
         if (numbers[0] == numbers[1] && numbers[1] == numbers[2])
         {
-            // fail the test
+            TEST_FAIL_MESSAGE("triple generated");
-            TEST_ASSERT(0);
         }
         free(numbers);
     }
 }
 
+// check if getDuplicate() modifies the original array (it should not)
+void test_get_duplicate_does_modify()
+{
+    unsigned int arr1[] = {1, 2, 3, 4, 5, 4, 3, 2, 1}; // sorting would change this
+    size_t len1 = sizeof(arr1) / sizeof(arr1[0]);
+    unsigned int arr1Copy[9];
+    memcpy(arr1Copy, arr1, len1 * sizeof(unsigned int));
+
+    getDuplicate(arr1, len1); // return value does not matter
+
+    // check if the arrays are still the same
+    if (memcmp(arr1, arr1Copy, len1 * sizeof(unsigned int)))
+    {
+        TEST_FAIL_MESSAGE("Arrays have diverged");
+    }
+}
+
+// checks if there is exactly 1 duplicate number at varying array sizes
+void test_exactly_one_duplicate()
+{
+    const size_t MAX_LIST_SIZE = 20;      // max tested array len
+    const size_t ITERATIONS_PER_LEN = 20; // number of iterations for each tested array len
+
+    for (size_t len = 2; len < MAX_LIST_SIZE; len++) // start with smallest sensible size 2
+    {
+        for (size_t i = 0; i < ITERATIONS_PER_LEN; i++)
+        {
+            unsigned int *randTestList = createNumbers((unsigned int)len);
+
+            qsort(randTestList, len, sizeof(unsigned int), compareInt);
+
+            int cntDuplicate = 0;
+            for (size_t j = 0; j < len - 1; j++)
+            {
+                if (randTestList[j] == randTestList[j + 1])
+                {
+                    cntDuplicate++;
+                }
+            }
+            // there should be exactly 1 duplicate
+            TEST_ASSERT_EQUAL_INT(1, cntDuplicate);
+
+            free(randTestList);
+        }
+    }
+}
+
+static int compareInt(const void *ptr1, const void *ptr2)
+{
+    unsigned int num1 = *(int *)ptr1;
+    unsigned int num2 = *(int *)ptr2;
+
+    if (num1 < num2)
+        return -1;
+    if (num1 > num2)
+        return 1;
+    return 0;
+}
+
 int main(void)
 {
     printf("============================\nNumbers tests\n============================\n");
     UNITY_BEGIN();
-    RUN_TEST(test_get_duplicate_error);
+    RUN_TEST(test_get_duplicate_without_duplicates);
     RUN_TEST(test_for_triple);
+    RUN_TEST(test_exactly_one_duplicate);
+    RUN_TEST(test_get_duplicate);
+    RUN_TEST(test_get_duplicate_does_modify);
     return UNITY_END();
 }

test_stack.c

@@ -15,6 +15,7 @@ void setUp(void)
 void tearDown(void)
 {
     clearStack(stack);
+    stack = NULL;
 }
 
 void test_push_and_pop(void)
@@ -31,17 +32,33 @@ void test_push_and_pop(void)
     stack = pop(stack);
 }
 
+// pop and top should return NULL if called with NULL ptr
 void test_handle_NULL(void)
 {
     TEST_ASSERT_NULL(pop(stack));
     TEST_ASSERT_NULL(top(stack));
 }
 
+void test_top(void)
+{
+    TEST_ASSERT_NULL(top(stack));
+    stack = push(stack, &data1);
+    TEST_ASSERT_EQUAL_PTR(top(stack), &data1);
+    TEST_ASSERT_EQUAL_INT(*(int *)top(stack), data1);
+    stack = push(stack, &data2);
+    TEST_ASSERT_EQUAL_PTR(top(stack), &data2);
+    TEST_ASSERT_EQUAL_INT(*(int *)top(stack), data2);
+    stack = push(stack, &data3);
+    TEST_ASSERT_EQUAL_PTR(top(stack), &data3);
+    TEST_ASSERT_EQUAL_INT(*(int *)top(stack), data3);
+}
+
 int main(void)
 {
     printf("============================\nStack tests\n============================\n");
     UNITY_BEGIN();
     RUN_TEST(test_push_and_pop);
     RUN_TEST(test_handle_NULL);
+    RUN_TEST(test_top);
     return UNITY_END();
 }