Lesson 7

Module Conclusion: Constructing a Dynamically Sized Stack in C++23

Use Case 2 critique

Conclusion is accurate but too generic: it lists outcomes without tying them to the actual refactored lesson sequence in this module.
Modern C++23 context is underused: the module teaches manual ownership (educational), but the conclusion should clearly contrast that with RAII and the Rule of Zero.
Missing “design takeaways”: readers should leave with a short checklist: invariants, copy/move policy, exception safety, and when to prefer std::stack/std::vector.
Code samples need minor modernization: prefer !s.empty() over s.size() > 0, and show idiomatic I/O and loop structure.

In this module you built a dynamically sized stack by modeling the stack as a C++ class and then refining that class across several focused lessons. The workflow pages you completed form a practical progression:

Module introduction: why “dynamic sizing” is an ownership problem (stack vs heap, allocation, deallocation).
intro-constructing-dynamicallySizedStack.php
Stack design choices: selecting a storage strategy (vector-backed vs node-based) and defining the ADT interface (push, pop, top, empty, size).
dynamically-sized-stack.php
Constructors: overloading constructors to support different initializations (default capacity, explicit capacity, string-based initialization).
stack-constructors.php
Copy constructors (usage): understanding when copying occurs (pass-by-value, return-by-value, initialization) and why copying must preserve invariants.
copy-constructors.php
Copy constructor design: implementing deep copy for owned memory so a stack can be safely cloned without double-delete bugs.
designing-copyConstructor.php
Destructors: releasing owned resources at end of lifetime and understanding when destructors run (scope exit, delete, exception unwinding).
cplusDestructor-usage.php

Put simply: you learned to treat a stack not just as a data structure, but as an object with invariants and ownership. The class encapsulates memory allocation, stack state, and safe copying so clients can use it correctly without knowing the internal details.

Key takeaways: what “dynamic sizing” really requires

Clear invariants: define what your members mean (capacity vs size, what top represents, what “empty” means).
Ownership is explicit: if your class uses new[], your class must also delete[] and must define safe copying.
Copy semantics are a design decision: either support deep copy (clone the buffer) or make the type move-only (common with unique ownership).
Exception safety matters: destructors should not throw, and constructors should leave the object either fully constructed or not constructed at all.

C++23 perspective: prefer RAII (Rule of Zero) when you can

This module intentionally exposes manual memory management because it teaches why constructors, copy constructors, and destructors exist. In production C++23, the most common best practice is to avoid raw owning pointers entirely by storing stack elements in RAII types:

std::vector<T> for contiguous storage (often fastest in practice)
std::deque<T> (often used under std::stack)
std::string for character buffers when “string behavior” is intended

When your class is composed of RAII members, the compiler-generated copy/move/destructor operations are typically correct automatically. That’s the Rule of Zero, and it dramatically reduces the chance of leaks and double frees.

Using a stack in the standard library

If you simply need a stack container, prefer std::stack (an adaptor) or a vector-backed approach:

#include <stack>
#include <string>
#include <iostream>

int main() {
    std::stack<std::string> s;
    s.push("Tom");
    s.push("Dick");
    s.push("Harry");

    while (!s.empty()) {
        std::cout << s.top() << "\n";
        s.pop();
    }
}

Where to go next

If you want to extend your ch_stack design further, C++23 offers a few natural upgrades:

Move support: implement move constructor/assignment so temporary stacks transfer ownership efficiently.
String-view input: add an overload that accepts std::string_view (keep the original const char* constructor for compatibility).
Safer storage: refactor char* to std::vector<char> and delete the manual destructor (Rule of Zero).
Capacity strategy: implement growth (e.g., doubling) so the stack expands as elements are pushed.

Completing this module means you can now read, design, and maintain class-based data structures with a sharper understanding of lifetime, copying, and resource ownership—skills that transfer directly to real systems code.