output the whole string in c++ using getline

Question

I wrote this code. It works in the main function

cout << "Enter the patron's name: ";
getline(std::cin, patron.name);
cout << "Enter the book title: ";
getline(std::cin, book.title);
cout << book.title << " is now checked out to " << patron.name << endl;

However, when I put it under a do while loop with switch case, it does not work anymore.

do {
        cout << endl << "? "; cin >> choice;
        switch (toupper(choice)){
        case 'T':           
            cout << "Enter the patron's name: ";
            getline(std::cin, patron.name);
            cout << "Enter the book title: ";               
            getline(std::cin, book.title);
            cout <<  book.title << " is now checked out to " << patron.name << endl;
            break;
           }[enter image description here][1]
} while (choice != 'Q' && choice!= 'q');

The input was like:

Could anyone explain to me why this happened? Thanks

Answer 1

After this statement

cout << endl << "? "; cin >> choice;

insert

std::cin.ignore( std::numeric_limits<std::streamsize>::max(), '\n' );

to remove the new line character (that corresponds to the pressed Enter key after the input) that is still in the input buffer, Otherwise a call of getline will read an empty string.

You should include the header <limits> to use the class numeric_limits

Answer 2

This \\n after T(your input) is being consumed by getline. That's why you are getting such behaviour. You need to flush the newline out of the buffer.

You can do this by adding this statement as shown.

std::cin.ignore (std::numeric_limits<std::streamsize>::max(), '\n');
cout << "Enter the patron's name: ";