qDebug Problem

QString a = "test\n";
qDebug() << a;

output of programm is "test\n"

Why it does not interptret correctly? I cannot write after every QString varaible with a \n in it toLatin1().data() to get an correct output.

Is there no simple solution in Qt?

thank you

qDebug() is doing exactly what you told it to: print the value of the QString variable "a". The value of "a" is a string composed of the letters 't', 'e', 's', 't', '\n'.

Think about what you are asking for - if qDebug() interpreted non-printing characters like '\t' or '\n', how would you ever be able to print the actual contents of a string that contained those? It's a tool to aid you in debugging, where you can ask it to print the actual contents of built-in types, Qt types, and custom types for which you have implemented the right operator<<().

qDebug() outputs types with default formatting. If you want qDebug to custom format your output, you can use QTextStream manipulators. qDebug() automatically inserts a newline after ever statement and inserts spaces between arguments separated by <<.

"qDebug() outputs types with default formatting. If you want qDebug to custom format your output, you can use QTextStream manipulators."

Can you explain pls?

It is explained in the QDebug and QTextStream documentation. Look for the section on manipulators in the QTextStream docs.

Try

Code:

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qDebug() << qSetFieldWidth( 8 ) << qSetRealNumberPrecision( 2 ) << 3.14159;
qDebug() << fixed << right << 3.14159;

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thank you_____

You could also do simpler things like:

Code:

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qDebug() << QString( "%1" ).arg( 3.14159, 8, 'f', 2 );

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which will produce the same output as the first line in the previous reply.