Open an external file from qt

[maider]

Hello,

I'm trying to open a .pdf file from qt. I have develop the following code to achieve my goal:

#include <QDesktopServices>
#include <QUrl>
 
exercise::exercise(QWidget *parent)
    : QWidget(parent)
{
	ui.setupUi(this);
	connect(ui.open,SIGNAL(clicked()),this,SLOT(openDocument()));
}
 
exercise::~exercise()
{
 
}
 
void exercise::openDocument()
{
	QDesktopServices desk;
	desk.openUrl(QUrl("file://C:/a.pdf"));
}

#include <QDesktopServices>
#include <QUrl>

exercise::exercise(QWidget *parent)
    : QWidget(parent)
{
	ui.setupUi(this);
	connect(ui.open,SIGNAL(clicked()),this,SLOT(openDocument()));
}

exercise::~exercise()
{

}

void exercise::openDocument()
{
	QDesktopServices desk;
	desk.openUrl(QUrl("file://C:/a.pdf"));
}

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Can someone help me? i have read the post about this thread, but i'm not capable to solve the problem.