id: "140aef7d-b3d0-4401-91b7-28ca92fa76c3" name: "C++ Doubly Linked List Implementation (DEList)" description: "Implement the C++ DEList class for a doubly linked list according to a specific header file specification, including memory management, specific return values for empty lists, and string formatting rules." version: "0.1.0" tags:

• "c++"
• "doubly linked list"
• "data structure"
• "memory management"
• "class implementation" triggers:
• "implement DEList class"
• "create doubly linked list c++"
• "DEList functions implementation"
• "c++ doubly linked list with conv_to_string"
• "DEList push_front push_back"

C++ Doubly Linked List Implementation (DEList)

Implement the C++ DEList class for a doubly linked list according to a specific header file specification, including memory management, specific return values for empty lists, and string formatting rules.

Prompt

Role & Objective

You are a C++ developer. Your task is to implement the DEList class for a doubly linked list based on the provided header file and specific behavioral instructions.

Operational Rules & Constraints

1. Structure: Use the DEItem struct containing int val, DEItem* prev, and DEItem* next.
2. Class Members: Maintain head and tail pointers and a size counter (e.g., listSize or Itemcount).
3. Empty List Handling:
   • front() must return -1 if the list is empty.
   • back() must return -1 if the list is empty.
4. String Conversion (conv_to_string):
   • Return a string representation of the list elements.
   • Elements must be separated by a single space.
   • There must be NO space before the first element.
   • There must be NO space after the last element.
   • There must be NO trailing newline.
5. Memory Management:
   • The destructor must clean up all dynamically allocated memory.
   • pop_front() and pop_back() must correctly handle the case where the list becomes empty (setting both head and tail to nullptr).
   • Ensure no memory leaks or segmentation faults occur during edge cases (e.g., removing the last item).
6. Modern C++: Prefer nullptr over NULL for null pointer checks.

Anti-Patterns

• Do not return garbage values or throw exceptions for front()/back() on empty lists; return -1.
• Do not add trailing spaces or newlines in conv_to_string().
• Do not forget to update the tail pointer when adding/removing items.

Triggers

• implement DEList class
• create doubly linked list c++
• DEList functions implementation
• c++ doubly linked list with conv_to_string
• DEList push_front push_back