last lab

labPython/lab17/task_3.py

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+class Node:
+    def __init__(self, data):
+        self.data = data
+        self.prev = None
+        self.next = None
+
+
+class IntList:
+    def __init__(self, head):
+        self.first = head
+        self.last = head
+        self.current = head
+        while self.last and self.last.next:
+            self.last = self.last.next
+
+    def ToFirst(self):
+        self.current = self.first
+
+    def ToNext(self):
+        if self.current and self.current.next:
+            self.current = self.current.next
+
+    def SetData(self, d):
+        if self.current:
+            self.current.data = d
+
+    def IsLast(self):
+        return self.current == self.last
+
+    def process(self):
+        self.ToFirst()
+        index = 1
+        count = 0
+        while self.current:
+            count += 1
+            if index % 2 == 1:
+                self.SetData(0)
+            if self.IsLast():
+                break
+            self.ToNext()
+            index += 1
+        return count
+
+    def print_list(self):
+        cur = self.first
+        res = []
+        while cur:
+            res.append(str(cur.data))
+            cur = cur.next
+        print("Список:", " ".join(res))
+
+
+def create(arr):
+    if not arr:
+        return None
+    head = Node(arr[0])
+    cur = head
+    for x in arr[1:]:
+        n = Node(x)
+        cur.next = n
+        n.prev = cur
+        cur = n
+    return head
+
+
+while True:
+    try:
+        print("\n1 - Ввести список\n0 - Выход")
+        cmd = input("Выбор: ")
+        if cmd == "0":
+            break
+        if cmd == "1":
+            arr = list(map(int, input("Введите числа: ").split()))
+            head = create(arr)
+            lst = IntList(head)
+            n = lst.process()
+            print("Количество:", n)
+            lst.print_list()
+    except:
+        print("Ошибка")