Qt 5.0 including personal header issues - c++

Question

look i'm kind of new to programming in c++ with Qt so i've downloaded the 5.0 version on my win 7 64 bit. i have made a class named Mafenetre and i implemented its code and it seems perfect but when i i try to run the main program it says
C:\Users\Zbart3i\Downloads\Programs\test\main.cpp:3: error: C1083: Cannot open include file: 'Mafenetre.h': No such file or directory
this is my pro code:
SOURCES += \
main.cpp \
mafenetre.cpp
QT+=widgets
HEADERS += \
mafenetre.h
this is code of Mafenetre.h:
#ifndef MAFENETRE_H
#define MAFENETRE_H
include < QtWidgets>
class Mafenetre:public QWidget
{
public:
Mafenetre();
private:
QPushButton *m_bouton;
};
#endif // MAFENETRE_H
this is Mafenetre's.cpp:
#include "mafenetre.h"
Mafenetre::Mafenetre():QWidget()
{
setFixedSize(300,150);
m_bouton=new QPushButton("pimp mon bouton",this);
m_bouton->setFont(QFont("monotype corsiva",15));
m_bouton->setCursor(Qt::PointingHandCursor);
}
and the main.cpp
#include< QtWidgets/QApplication>
#include< QtWidgets>
#include< Mafenetre.h>
void main(int argc, char *argv[])
{
QApplication app(argc, argv);
Mafenetre fenetre;
fenetre.show();
app.exec();
}

Answer 1

In C++, you should use the #include "name", not #include (Quote marks instead of triangle brackets), as they have different meanings.
#include looks in certain directories where libraries (including the standard library) is installed.
#include "name" looks first in your project's folders, and then checks the other directories.
Well, to be technically accurate, what folders they look in, and in one order, is compiler-specific.
This:
#include <Mafenetre.h>
Should be this:
#include "Mafenetre.h"
Read this:
MinGW #include search directories
Other Directories Searched by Default
The minimal list of directories, identified as described
above, specifies the only locations which will be searched by default,
for system header files or for headers associated with user installed
libraries; however, there is one exception. Astute readers may have
noticed that the include file search path is itemised in a pair of
sequential lists, with the second being concatenated to the first;
however, the first, identified as the #include "..." search list
appears to be empty. In reality, this apparent emptiness is possibly
misleading; unless the user specifies the "-I-" option when invoking
GCC, this list contains exactly one directory: the directory in which
the source file containing the #include "file" directive resides.
Notice that this one additional directory is not searched for headers specified with the #include <file> form of the #include directive; it applies only for those headers specified using the #include "file" form of the directive.
And make sure your "Mafenetre.h" file is in the same folder as your main.cpp file. Otherwise you need to do #include "folderPath/fileName.h", and also add the path to the SOURCES or HEADERS variables in the .pro file.
Also make sure the spelling is identical, and that the proper case is used - sometimes it matters, sometimes it doesn't.
If you are still having trouble, try to compile a simple project consisting of just a single main.cpp, to make sure everything is installed correctly.

Answer 2

Are you sure you have included the right header. Also i don't see you using the QObject macro in your header file. It should be something like this:
Mafenetre.h:
#ifndef MAFENETRE_H
#define MAFENETRE_H
#include <QWidget>
class Mafenetre : public QWidget
{
Q_OBJECT
public:
explicit Mafenetre(QWidget *parent = 0);
signals:
public slots:
};
#endif // MAFENETRE_H
Mafenetre.cpp:
#include "mafenetre.h"
Mafenetre::Mafenetre(QWidget *parent) :
QWidget(parent)
{
}
Finally you main.cpp should be like this, check the headers:
......
#include "mafenetre.h"
int main(int argc, char *argv[])
{
QApplication a(argc, argv);
Mafenetre m;
m.show();
return a.exec();
}