Step 7 of 8

The rule of zero

Everything in the last few steps (destructor, deep copy, copy-and-swap) is only needed because the class held a raw owning pointer. Replace it with a member that already manages itself, like std::vector, std::string or std::unique_ptr, and you write none of them. The compiler-generated versions just do the right thing, member by member.

That's the rule of zero, and it's how most modern C++ classes are written. Writing your own destructor or copy operations is the exception, reserved for low-level resource wrappers.

class Loadout {
    std::vector<std::string> items_;   // copies, moves and frees itself
public:
    void add(std::string item) { items_.push_back(std::move(item)); }
};

Your turn: write class Inventory with the rule of zero: void add(const std::string& item), int count() const, bool has(const std::string& item) const, void clear(). No new, no delete, no destructor.

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