Qt, QTextStream - inputting a char/string into an int

Question

Consider the following program:

int num;

QTextStream(stdin) >> num;

QTextStream(stdout) << num;

Like this, if I am to incorrectly input a string, or a char, into the variable num, its value becomes 0 by default.

How can I change the behavior of QTextStream, so that it stores a different value for incorrect inputs? For example, -1?

You could subclass QTextStream and overrload the operator>>(int). — Bernhard Heinrich, Jul 28 '16 at 07:03

score 2 · Accepted Answer · answered Jul 27 '16 at 15:57

You cannot change this behavior, but you can check QTextStream::status() for QTextStream::ReadCorruptData.

int num;

QTextStream input(stdin);
input >> num;

if (input.status() == QTextStream::ReadCorruptData)
    num = -1;

QTextStream(stdout) << num;

1 Answers1