[Qt-interest] Problems With tr and operator <<

[Aaron Lewis]

Sorry for sending this mail to all these address. ;-)

Hi , I was reading your book , Qt/C++ Advance Programming.
Part 12.5 , you write a image converter

I rewrited this program , and add some new functions

-snip-

        if(ui->colorBox->isChecked())
          //  arg << tr("-depth
%1").arg(ui->colorComboBox->currentText());   //fails  , convert doesn't
recognize '-depth 32'
            arg << "-depth" << ui->colorComboBox->currentText();   //
works , don't know why

-snip-

Fist method doesn't work , while the second works , convert program
tells me '-depth 32' is not recognized.
Is there any differences between `tr' and operator `<<' ?

Any ideas will appreciate ;-)

-- 
Best Regards,
Aaron Lewis - PGP: 0x4A6D32A0
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