completed numbers

I2_Dobble/numbers.c

@@ -14,13 +14,74 @@
 // 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.
+static int compare(const void *a, const void *b) 
+{
+    return (*(int *)a > *(int *)b) - (*(int *)a < *(int *)b);
+}
+
 unsigned int *createNumbers(unsigned int len)
 {
+    if (len < 2) 
+        return NULL;
 
+    unsigned int *numbers = malloc(sizeof(unsigned int) * len);
+
+    if (!numbers) 
+        return NULL;
+
+    srand(time(NULL));
+
+    TreeNode *root = NULL;
+
+    unsigned int i = 0;
+    while (i < len - 1) 
+    {
+        unsigned int val = (rand() % (2 * len)) + 1;
+        int isDup = 0;
+
+        root = addToTree(root, &val, sizeof(unsigned int), compare, &isDup);
+
+        if (!isDup) 
+        {
+            numbers[i++] = val;
+        }
+    }
+
+    // Duplicate one random entry
+    unsigned int dupIndex = rand() % (len - 1);
+    numbers[len - 1] = numbers[dupIndex];
+
+    clearTree(root); //Notwendigkeit muss noch restlichem Code entnommen werden
+    return numbers;
 }
 
 // Returns only the only number in numbers which is present twice. Returns zero on errors.
 unsigned int getDuplicate(const unsigned int numbers[], unsigned int len)
 {
+    if (!numbers || len < 2) 
+        return 0;
 
-}
+    unsigned int *numbersCopy = malloc(sizeof(unsigned int) * len);
+    if (!numbersCopy) 
+        return 0;
+
+    for (unsigned int i = 0; i < len; i++) 
+    {
+        numbersCopy[i] = numbers[i];
+    }
+
+    qsort(numbersCopy, len, sizeof(unsigned int), compare);
+
+    unsigned int duplicate = 0;
+    for (unsigned int i = 0; i < len - 1; i++) 
+    {
+        if (numbersCopy[i] == numbersCopy[i+1]) 
+        {
+            duplicate = numbersCopy[i];
+            break;
+        }
+    }
+
+    free(numbersCopy);
+    return duplicate;
+}