Is there a way to keep on looping a switch statement if a user enters anything other than an integer in c++?

Question

My loop works for a scenario where a user enters a number not in the list but when I insert a character or string, the loop does'nt work. I wanted to make it such that it'll keep on looping as long as the switch statement case is default, irregardles of whether its a number or character. I tried choice!=int and choice==string to create a while loop but apparently its not possible.

void userDetails();
int main()
{
    userDetails();
    return 0;
}
void userDetails()
{
    cout << "Select a username below:" << endl;
    cout << "1. " << firstname + lastname << flush << endl;
    cout << "2. " << lastname + firstname << flush << endl;
    cout << "3. " << firstname + "254" << flush << endl;
    cout << "4. " << lastname + "254" << flush << endl;
    cout << "5. Enter other username:" << flush << endl;
    int choice;
    cin >> choice;
    switch (choice)
    {
    case 1:
        username = firstname + lastname;
        cout << "You have selected " << username << " as your username" << flush << endl;
        break;
    case 2:
        username = lastname + firstname;
        cout << "You have selected " << username << " as your username" << flush << endl;
        break;
    case 3:
        username = firstname + "254";
        cout << "You have selected " << username << " as your username" << flush << endl;
        break;
    case 4:
        username = lastname + "254";
        cout << "You have selected " << username << " as your username" << flush << endl;
        break;
    case 5:
        cout << "Create a username:" << endl;
        cin >> username;
        cout << "You have selected " << username << " as your username" << flush << endl;
        break;
    default:
        cout << "Invalid option, please try again!!!!";
        break;
    }
    while (choice > 5)
    {
        cout << "Select a username below:" << endl;
        cout << "1. " << firstname + lastname << flush << endl;
        cout << "2. " << lastname + firstname << flush << endl;
        cout << "3. " << firstname + "254" << flush << endl;
        cout << "4. " << lastname + "254" << flush << endl;
        cout << "5. Enter other username:" << flush << endl;
        cin >> choice;
        switch (choice)
        {
        case 1:
            username = firstname + lastname;
            cout << "You have selected " << username << " as your username" << flush << endl;
            break;
        case 2:
            username = lastname + firstname;
            cout << "You have selected " << username << " as your username" << flush << endl;
            break;
        case 3:
            username = firstname + "254";
            cout << "You have selected " << username << " as your username" << flush << endl;
            break;
        case 4:
            username = lastname + "254";
            cout << "You have selected " << username << " as your username" << flush << endl;
            break;
        case 5:
            cout << "Create a username:" << endl;
            cin >> username;
            cout << "You have selected " << username << " as your username" << flush << endl;
            break;
        default:
            cout << "Invalid option, please try again!!!!";
            break;
        }
    }
    while (choice ==0)
    {
        cout << "Select a username below:" << endl;
        cout << "1. " << firstname + lastname << flush << endl;
        cout << "2. " << lastname + firstname << flush << endl;
        cout << "3. " << firstname + "254" << flush << endl;
        cout << "4. " << lastname + "254" << flush << endl;
        cout << "5. Enter other username:" << flush << endl;
        cin >> choice;
        switch (choice)
        {
        case 1:
            username = firstname + lastname;
            cout << "You have selected " << username << " as your username" << flush << endl;
            break;
        case 2:
            username = lastname + firstname;
            cout << "You have selected " << username << " as your username" << flush << endl;
            break;
        case 3:
            username = firstname + "254";
            cout << "You have selected " << username << " as your username" << flush << endl;
            break;
        case 4:
            username = lastname + "254";
            cout << "You have selected " << username << " as your username" << flush << endl;
            break;
        case 5:
            cout << "Create a username:" << endl;
            cin >> username;
            cout << "You have selected " << username << " as your username" << flush << endl;
            break;
        default:
            cout << "Invalid option, please try again!!!!";
            break;
        }
    }
}   

Answer 1

I think you can do as below.

1. read a string instead of integer.
2. parse string to integer.
3. if there are parsing error or less than 1 or greater than 5, run while loop again.

Answer 2

Instead of declaring an int and using it as a number, you can declare a character and only use it as a number when it actually is a number, something like (pseudo-code):

char str_choice;
cin >> str_choice;
if ((str_choice <= '9') && (str_choice >= 0))
{
  int choice = (int)str_choice - (int)'0'; // this part you might need to rework
  switch (choice)
  ...
} else
  cout << "You have not entered an integer, so you have lost the game" << endl;