Shared Pointer Ownership

Question

Problem: Shared Pointer Ownership. Solve this hands-on electronics task on EWskills.

Accepted Answer

#include 
#include 
#include 
using namespace std;

class DataStore {
    vector data;

public:
    DataStore(int n) : data(n) {
        cout << "Data created" << endl;
    }

    ~DataStore() {
        cout << "Data destroyed" << endl;
    }

    void readInput() {
        for (int& v : data) {
            cin >> v;
        }
    }

    void print() const {
        for (size_t i = 0; i < data.size(); i++) {
            cout << data[i];
            if (i + 1 < data.size()) cout << " ";
        }
        cout << endl;
    }
};

// shared_ptr passed by value → shared ownership
void printInFunction(shared_ptr store) {
    cout << "Printed in function" << endl;
    store->print();
}

int main() {
    int N;
    cin >> N;

    {
        shared_ptr store = make_shared(N);

        store->readInput();

        printInFunction(store);

        cout << "Printed in main" << endl;
        store->print();
    }

    return 0;
}

Explanation & Logic Summary:

std::shared_ptr allows multiple owners to manage the same object.
In this program, both main() and printInFunction() hold ownership of the same DataStore.
The object remains alive until the last owner goes out of scope, ensuring safe access in multiple execution contexts.
The destructor runs exactly once when ownership ends.

Firmware Relevance & Real-World Context:

In embedded Linux and RTOS-based systems, data such as sensor samples, lookup tables, or configuration blocks may be produced once and consumed by multiple processing stages.
std::shared_ptr enables this shared access safely when lifetime cannot be statically determined, but must be used carefully due to runtime overhead and ownership complexity.

80. Shared Pointer Ownership