CODEWITHSUNDEEP
c++objectprogram-entry-point
user3371750
user3371750

Reputation:

C++ - Looping main resetting objects

I have an issue where I am creating a basic text user interface. In order to keep the text interface looping, I call main() until the user chooses to quit by pressing 0.

However, this recreates my LinkedList list, which I would like to keep as a permanent. I understand that it is bad practice to have it as a global variable, so how can I get around this issue? 

int main() {

    int choice, newLatitude, newLongitude;
    string newName;

    LinkedList list;

    cout << "[1] Add a city \n";
    cout << "[2] Display list of cities \n";
    cout << "[0] Exit program \n";
    cin >> choice;
    if (choice == 0) {
        return 0;
    }
    else if (choice == 1) {
        cout << "Enter city name: ";
        cin >> newName;
        cout << "Enter latitude: ";
        cin >> newLatitude;
        cout << "Enter longitude: ";
        cin >> newLongitude;
        City newCity(newName, newLatitude, newLongitude);
        list.addNode(newCity);
    } 
    else if (choice == 2) {
        list.display();
    }
    else {
        cout << "Invalid option, please try again \n";
    }

        main();

    return 0;
}

Upvotes: 0

Views: 49

Answers (1)

marsh
marsh

Reputation: 2740

It is probably not a good idea to use recursion to do this task. If you want it to repeat you are probably better off with a while loop. http://msdn.microsoft.com/en-us/library/2aeyhxcd.aspx

While(true) will loop as long as the statement (true) is true. Aka forever. You could also do something like while(choice != 0) though that would require a slight rework of your code.

int main() {

    int choice, newLatitude, newLongitude;
    string newName;

    LinkedList list;

    while(true)
    {
        cout << "[1] Add a city \n";
        cout << "[2] Display list of cities \n";
        cout << "[0] Exit program \n";
        cin >> choice;
        if (choice == 0) {
            return 0;
        }
        else if (choice == 1) {
            cout << "Enter city name: ";
            cin >> newName;
            cout << "Enter latitude: ";
            cin >> newLatitude;
            cout << "Enter longitude: ";
            cin >> newLongitude;
            City newCity(newName, newLatitude, newLongitude);
            list.addNode(newCity);
        } 
        else if (choice == 2) {
            list.display();
        }
        else {
            cout << "Invalid option, please try again \n";
        }
    }
    return 0;
}

Upvotes: 1

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