len() funktion, fix pop() funktion, assertions in starten.py

linked-lists/linked_list.py

@@ -55,17 +55,38 @@ class LinkedList:
 
     def pop(self) -> int | None:
         if self.head is None:
-            self.head = None
             return None
 
         node = self.head
+
         assert node is not None
 
-        while True:
         if node.next is None:
-                return node.data
+            data = node.data
+            self.head = None
+            return data
+
+        assert node.next is not None
+
+        while True:
+            prev_node = node
             node = node.next
 
+            if node.next is None:
+                data = node.data
+                prev_node.next = None
+                return data
+
+    def len(self) -> int:
+        node = self.head
+        i = 0
+
+        while node is not None:
+            node = node.next
+            i += 1
+
+        return i
+
     def print(self):
         node = self.head
         while node is not None:

linked-lists/starten.py

@@ -1,15 +1,26 @@
 from linked_list import LinkedList
 
 list = LinkedList()
+assert list.len() == 0
 list.push(123)
+assert list.len() == 1
 list.push(456)
+assert list.len() == 2
 list.push(789)
-# list.insert(00000, 1)
+assert list.len() == 3
+list.insert(-10, 1)
 list.print()
+assert list.len() == 4
+print(list.len())
 
 print(list.pop())
+assert list.len() == 3
 print(list.pop())
+assert list.len() == 2
 print(list.pop())
+assert list.len() == 1
+print(list.pop())
+assert list.len() == 0
 
 
 # node3 = Node(333)