Question

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Why is this cin reading jammed?

I overloaded the istream operator (istream &operator>>...) and it takes in a Point of the format:

(<x-coordinate>,<y-coordinate>)

I want to test this out multiple (10) times, and so have written:

for (int i = 0; i < 10; i++)  {
    cin >> a;
    if (!cin.fail()) { cout << a << endl; }
    else { cout << "Invalid input!" << endl; cin.clear(); }
}

EDIT:

I now have the following code:

for (int i = 0; i < 10; i++)  {
    cin >> a;
    if (!cin.fail()) { cout << a << endl; }
    else {
        cout << "Invalid input!" << endl; cin.clear();
        while (!cin.eof()) { cin.ignore(); } cin.ignore();
    }
}

The ignore was suggested by Cthulhu. However, the problem is cin still outputs “Invalid input!” after running through the code above:

(3,3) <-- input
(3,3) <-- output
Invalid output! <-- second output

Is there a way that I can clear what is in cin?

Answer 1

cin.clear() does not empty the buffer, it resets error flags on the stream.
You then have to call cin.ignore

istream&  ignore ( streamsize n = 1, int delim = EOF );

Extracts characters from the input sequence and discards them.

The extraction ends when n characters have been extracted and
discarded or when the character delim is found, whichever comes first.
In the latter case, the delim character itself is also extracted.

---

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

Numeric Limits