如何在Qt QMessageBox中添加变量值？

Question

printf("This machine calculated all prime numbers under %d %d times in %d 
  seconds\n", MAX_PRIME, NUM_OF_CORES, run_time);

I want this output to be printed in QMessageBox text Box.

I have gone through QMessageBox documentation didn't find anything helpful.

Answer 1

QMessageBox has nothing for it because it's none of its business - it just displays strings as you passed them. However, QString does provide methods for formatting data replacing placeholders using the arg method:

QMessageBox::information(parent,
     QString("This machine calculated all prime numbers under %1 %2 times in %3 seconds")
         .arg(MAX_PRIME)
         .arg(NUM_OF_CORES)
         .arg(run_time), "Message title");

http://doc.qt.io/qt-5/qstring.html#argument-formats

http://doc.qt.io/qt-5/qstring.html#arg

Answer 2

First of all you must fill QString for you QMessageBox . You can do it with method arg of QString . Then you can show message box with static method information of QMessageBox. In your case code will be:

QMessageBox::information(nullptr/*or parent*/, "Title",  
    QString("This machine calculated all prime numbers under %1 %2 times in %3 seconds")
    .arg(MAX_PRIME).arg(NUM_OF_CORES).arg(run_time));