how to read coordinates points from text file

[rafik]

Hello,

i want to read points coordinats from a text file, how can i do that please?

2.0000000e+000 8.1000000e+001
3.0000000e+000 6.9000000e+001
6.0000000e+000 1.5500000e+002
1.2000000e+001 1.2400000e+002
1.2000000e+001 2.2800000e+002
2.4000000e+001 1.9200000e+002
2.4000000e+001 2.1600000e+002
2.8000000e+001 2.3700000e+002

there are spaces between the X and Y coordinates
help me please and thank you.

[anda_skoa]

QFile, QTextStream::readLine(), QString::split().

Cheers,
_

[rafik]

Thank you for your reply, but i tried this and i have a runTime error


#include <QApplication>
#include <QtWidgets>

int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QWidget f;

QFile monFichier("C:/Users/amine/Downloads/dcis/dcis1.txt");

double x = 0.0;
double y = 0.0;

QTextStream ts(&monFichier);
QString line;
line = ts.readLine();
QStringList s = line.split(" ",QString::SkipEmptyParts);
x = s.at(0).toDouble();
y = s.at(1).toDouble();

QLCDNumber *lcd1 = new QLCDNumber(&f);
lcd1->setSegmentStyle(QLCDNumber::Flat);
lcd1->move(100, 100);
QLCDNumber *lcd2 = new QLCDNumber(&f);
lcd2->setSegmentStyle(QLCDNumber::Flat);
lcd2->move(170, 100);

lcd1->display(x);
lcd2->display(y);
f.show();


return app.exec();

}


Added after 10 minutes:

there are some spaces in the begining and between the coordinates

[Lesiok]

Read about QString::trimmed() - manual is the best friend the programmer.

[yeye_olive]

If I remember correctly, QTextStream's extraction operator (>>) interprets whitespace as a separator between values. Perhaps all you have to do is:

double x, y;
ts >> x >> y;

[rafik]

thank you all for your replies :), yeye_olive your instruction give the result, thank you

Added after 31 minutes:

i have another problem, i don't want to read the last line in the text file, because if i do a loop and read the coordinates the program display x as 0.0 and y as 0.0
so my question is : to stop reading coordinates when it reaches the line before the last line if it is possible.
How can i do that please.


#include <QApplication>
#include <QtWidgets>


int main(int argc, char *argv[])
{
QApplication app(argc, argv);
QWidget f;

QFile monFichier("C:/Users/amine/Downloads/dcis/dcis1.txt");
monFichier.open(QIODevice::ReadOnly);

double x = 0.0;
double y = 0.0;

QTextStream ts(&monFichier);
while(!ts.atEnd())
{
ts >> x >> y;
}

QLCDNumber *lcd1 = new QLCDNumber(&f);
lcd1->setSegmentStyle(QLCDNumber::Flat);
lcd1->move(100, 100);
QLCDNumber *lcd2 = new QLCDNumber(&f);
lcd2->setSegmentStyle(QLCDNumber::Flat);
lcd2->move(170, 100);

lcd1->display(x);
lcd2->display(y);
f.show();

return app.exec();

}

[Lesiok]

Read data with first method (readLine()) and test whether the length is greater then 0.