cin and getline skipping input [duplicate]

问题

earlier i posted a question about cin skipping input, and I got results to flush, and use istringstream, but now I tried every possible solution but none of them work.

here is my code:

void createNewCustomer () {
    string name, address;

    cout << "Creating a new customer..." << endl;
    cout << "Enter the customer's name: "; getline(cin, name);
    cout << "Enter the customer's address: "; getline(cin, address);

    Customer c(name, address, 0);
    CustomerDB::addCustomer(c);

    cout << endl;
}

but I'm still getting the same thing, skipping input, and when it does take input, it takes them and stores in name empty nothing, and in address it takes what i wrote in name but from the 2nd letter to the end

what is wrong with my code?

I tried the cin.ignore(), cin.get(), and cin.clear() all of them together and alone, none of them worked

EDIT:

main method in main.cpp invokes mainMenu() only

void mainMenu () {
    char choice;

    do {
        system("cls");
        mainMenuDisplay();
        cin >> choice;
        system("cls");

        switch (choice) {
            case '1':
                customerMenu();
                break;

            case '2':
                dvdMenu();
                break;

            case '3':
                receiptMenu();
                break;

            case '4':
                outro();
                break;

            default:
                cout << '\a';
        }

        cin.ignore();
        cin.get();
    } while (choice != '4');
}

i will choose 1 for the customer example, this is customerMenu()

void customerMenu () {
    char choice;

    do {
        system("cls");
        manageCustomerMenu();
        cin >> choice;
        system("cls");

        switch (choice) {
            case '1':
                createNewCustomer();
                break;

            case '2':
                deleteCustomer();
                break;

            case '3':
                updateCustomerStatus();
                break;

            case '4':
                viewCustomersList();
                break;

            case '5':
                mainMenu();
                break;

            default:
                cout << '\a';
        }

        cin.ignore();
        cin.get();
    } while (choice != '5');
}

I choose 1 again to create a new customer object, which will now go to the MainFunctions.cpp which will invoke the function createNewCustomer() which is the first one.

void createNewCustomer () {
    string name, address;

    cout << "Creating a new customer..." << endl;
    cout << "Enter the customer's name: "; cin.getline(name,256);
    cout << "Enter the customer's address: "; cin.getline(address,256);

    Customer c(name, address, 0);
    CustomerDB::addCustomer(c);

    cout << endl;
}

回答1:

If you're using getline after cin >> something, you need to flush the newline out of the buffer in between.

My personal favourite for this if no characters past the newline are needed is cin.sync(). However, it is implementation defined, so it might not work the same way as it does for me. For something solid, use cin.ignore(). Or make use of std::ws to remove leading whitespace if desirable:

int a;

cin >> a;
cin.ignore (std::numeric_limits<std::streamsize>::max(), '\n'); 
//discard characters until newline is found

//my method: cin.sync(); //discard unread characters

string s;
getline (cin, s); //newline is gone, so this executes

//other method: getline(cin >> ws, s); //remove all leading whitespace

回答2:

The structure of your menu code is the issue:

cin >> choice;   // new line character is left in the stream

 switch ( ... ) {
     // We enter the handlers, '\n' still in the stream
 }

cin.ignore();   // Put this right after cin >> choice, before you go on
                // getting input with getline.

回答3:

Here, the '\n' left by cin, is creating issues.

do {
    system("cls");
    manageCustomerMenu();
    cin >> choice;               #This cin is leaving a trailing \n
    system("cls");

    switch (choice) {
        case '1':
            createNewCustomer();
            break;

This \n is being consumed by next getline in createNewCustomer(). You should use getline instead -

do {
    system("cls");
    manageCustomerMenu();
    getline(cin, choice)               
    system("cls");

    switch (choice) {
        case '1':
            createNewCustomer();
            break;

I think this would resolve the issue.