CODEWITHSUNDEEP
c++qt
daan
daan

Reputation: 43

Qt console application problems when reading input

When I try to get input from a Qt console application the program is not working as I expect it to. The following works as expected:

#include <QCoreApplication>
#include <QTextStream>

QTextStream cout(stdout);
QTextStream cin(stdin);

int main()
{
    QString msg("Hello world!");
    cout << msg << endl;

    return 0;
}

Output: 

Hello world!

But as soon as I add,

... 
int main()
{
    QString msg("Hello world!");
    cout << msg << endl;

    cout << "Enter new message: ";
    msg = cin.readLine();
    cout << endl << msg << endl;

    return 0;
}

Output:

Hello world!

is displayed but then the program waits for the input before displaying the prompt to enter text, instead of first displaying the prompt and THEN reading the input. The entered text displays together with (after) the prompt when entered.

I've been trying to resolve this for a couple of hours to no avail.

Upvotes: 4

Views: 2779

Answers (2)

frogatto
frogatto

Reputation: 29285

Also you can use:

cout << "Enter new message: " << flush;
  • std::flush just flushes the stdout stream.
  • std::endl besides adding a new line to the stdout, it also flushes the stream.

Upvotes: 1

CapelliC
CapelliC

Reputation: 60034

you should flush the output stream:

cout.flush();

that could also be written

(cout << "Enter new message: ").flush();

Upvotes: 3

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