QT: QString to Hexadecimal

Question

0.00/5 (No votes)

See more:

I know this is a very basic question but I'm newbie in Qt and I don't know to do it. I'm trying to convert a QString value (like "FF") to hexadecimal. I would like to obtain 0xFF. I am looking something like that

Source QString str= "20FF";
Target Result int hex= 0x20FF;

Could you help me? thanks.

Posted 8-Dec-15 23:44pm

Ramiien

Updated 18-Sep-19 18:56pm

Add a Solution

2 solutions

Add a Solution

Add your solution here

Treat my content as plain text, not as HTML

Preview 0

…

Existing Members

Sign in to your account

...or Join us

Download, Vote, Comment, Publish.

Your Email
Password
Forgot your password?

Your Email
This email is in use. Do you need your password?
Optional Password

I have read and agree to the Terms of Service and Privacy Policy
Please subscribe me to the CodeProject newsletters

When answering a question please:

Read the question carefully.
Understand that English isn't everyone's first language so be lenient of bad spelling and grammar.
If a question is poorly phrased then either ask for clarification, ignore it, or edit the question and fix the problem. Insults are not welcome.
Don't tell someone to read the manual. Chances are they have and don't get it. Provide an answer or move on to the next question.

Let's work to help developers, not make them feel stupid.

This content, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)

CPallini · Answer 1 · 2015-12-09T00:04:00

Solution 1

There is NO 'convert to Hexadecimal', actually.
str is the hexadecimal representation of the 8447 number.
0x20FF is just the literal[^] you could use in order to specify the number in the source code.

[update]
In order to compare the number represented by the string str with an actual int value, you have first to convert str to integer, using 16 as base. See "int QString::toInt(bool * ok = 0, int base = 10) const"[^]
[/update]

Posted 9-Dec-15 0:04am

CPallini

Updated 9-Dec-15 0:24am

v2

Comments

Ramiien 9-Dec-15 6:16am

Problem i am facing is I want to compare two values. Value from Network is in QString str= 20FF. and value in QHash is int value= 20FF.

CPallini 9-Dec-15 6:24am

Have a look at my updated solution.

CPallini 9-Dec-15 7:05am

QString provides the toLongLong method.

Jochen Arndt 9-Dec-15 7:05am

For 64-bit values use QString::toULongLong(NULL, 16) or QString::toULongLong(NULL, 0) when your string begins with "0x".
See http://doc.qt.io/qt-5/qstring.html#toULongLong.

But note that the QString::toXXX functions fail when there are other characters (not only the plain number string). For these cases you may also use the standard C function strtoull() passing str.ToLocal8Bit().data().

Member 14597349 · Answer 2 · 2019-09-18T18:56:00

Solution 2

QFile file("data.dat");
QByteArray Hex;
if (!file.open(QIODevice::ReadOnly))
{
;
}

Hex = file.readAll();
unsigned char hex[262182];
qint32 start = 0, size = 262182;
::memcpy(hex + start,Hex.constData(), size);

Posted 18-Sep-19 18:56pm

Member 14597349

Comments

Richard Deeming 19-Sep-19 12:33pm

An unexplained, unformatted code-dump is not a solution.