Silly? problem with QString

[A Former User]

Hi!

I'm just started work with Qt maybe week ago. I'm learning cpp for four years so I hope the adventure with Qt will be quite exciting ;)

I tried to search in many places, but still I have silly problem with QString in console application.

I'm trying to write QString on standard output with using cout

@
QString txt = "blabla";
cout << txt;
@

but it will not compile:

@
no match for 'operator <<' in 'std::cout << txt'
@

But for me it's weird, because I found (in documentation), that << operator is overloaded in QString. And, as far as I know, when we overload operator in class we can use is "normally". As if it was in built-in type.

I found solution:

@
QString txt = "blabla";

string txt2 = qstrdup(txt.toLatin1());

cout << txt;

@

But it's not convincing me. Is there quicker way to write QString in console? For example some write function (I mean: txt2.write(), or write(txt))

[A Former User]

Many Qt developers using qDebug(), but you can use this if you need std::cout:
@
cout << qPrintable(txt);
@

[quote author="luka.v.pikor" date="1278592314"]But it&#39;s not convincing me. Is there quicker way to write QString in console? For example some write function (I mean: txt2.write(), or write(txt))
[/quote]

@
QTextStream(stdout) << txt;
@

[A Former User]

P.S.: need feature for remove or/and join posts
P.S.: questions like that need a posting to "Desktop":http://developer.qt.nokia.com/forums/viewforum/10/ section

[A Former User]

@
QTextStream(stdout) << txt;
@

works perfectly! Thanks!

But what is qPrintable? I can't find it(http://doc.qt.nokia.com/4.6/classes.html) in opposite to qDebug().

Also, I have the same problem with QDate.

@
QDate d1(2010,1,1);
@

The TextStream didn't work. I assume that I have to use similar function. Or maybe convert Date type to string format?

[DenisKormalev]

[quote author="luka.v.pikor" date="1278593533"]@
Also, I have the same problem with QDate.
@
QDate d1(2010,1,1);
@
The TextStream didn&#39;t work. I assume that I have to use similar function. Or maybe convert Date type to string format?
[/quote]

Use QDate::toString() methods firstly.

[A Former User]

[quote author="luka.v.pikor" date="1278593533"]
But what is qPrintable? I can&#39;t find it(http://doc.qt.nokia.com/4.6/classes.html) in opposite to qDebug().
[/quote]
You can found this function in QtGlobal module, it's equivalent

@str.toLocal8Bit().constData()@

[quote author="luka.v.pikor" date="1278593533"]
Also, I have the same problem with QDate.
The TextStream didn&#39;t work.
[/quote]
For debugging purpose you can use qDebug(), this function have overloaded operator "<<" for many Qt classes.
@qDebug() << QDate(2010,1,1);@

[quote author="luka.v.pikor" date="1278593533"]
I assume that I have to use similar function. Or maybe convert Date type to string format?
[/quote]

Yes, you must use method toString() for this:

@QTextStream(stdout) << QDate(2010,1,1).toString();@

[A Former User]

Thanks Denis and Sabrog for helping me. Now it works!

[A Former User]

[quote author="SABROG" date="1278592777"]P.S.: need feature for remove or/and join posts
P.S.: questions like that need a posting to "Desktop":http://developer.qt.nokia.com/forums/viewforum/10/ section[/quote]

Thanks, I've moved it to Desktop now. A moderator can move, merge, split, and delete - but we haven't really begun finding moderators.

[A Former User]

[quote author="MariusG" date="1278595484"]A moderator can move, merge, split, and delete
[/quote]

I think users must have feature for delete own post. About merging, if user post message, forum engine must check, if previous post author in current thread a same, then just auto merge posts if elapsed less than 5-10 minutes. If future merged post have more than character forum limit size, then not merge.

[ixSci]

[quote author="luka.v.pikor" date="1278592314"]Hi!
And, as far as I know, when we overload operator in class we can use is "normally". As if it was in built-in type.
[/quote]
It's not actually right. You have to have global <<(>>) operator when one of the argument is istream\ostream and second is your type. QString doesn't have this operator but feel free to create your own for the convenient using. @std::ostream& operator<<(std::ostream& xOut, const QString& xStr)
{
xOut << xStr.toStdString();
return xOut;
}@
Also, in addition to answers above I see another solution: QString::toStdString would be appropriate function for your purpose