Display and divide the image

[kiransu123]

hi
i m kiran suryawanshi
i m final year student i m working on the project called as "tiled image viewer"
In this i suppose to display image on tiled display i.e four monitors clustered together
for that i hv to display and divide the image
so i write the following code but i had problem saying that "Segmentation fault"

i m represting problem area btn <problem></problem> tag
plz help me

#include "qgl.h"
#include "qapplication.h"
#include "qimage.h"
#include "iostream.h"
#include "GL/gl.h"
class Radha : public QGLWidget
{
	public:
		Radha(const QString &filename,QWidget *parent=0);
		void paintGL();
		void resizeGL(int w,int h);
		void divide();
	protected:
		QImage data,gldata;
};
 
Radha::Radha(const QString &filename,QWidget *parent):QGLWidget(parent){
	data.load(filename);
	gldata=QGLWidget::convertToGLFormat(data);
	resize(data.size());
 
}
 
void Radha::paintGL(){
	int k,i,j,count=0,flag=1;	
<PROBLEM>	
	uchar *temp;
	uchar *img;
	temp=gldata.bits();
 
	for(j=0;j<data.width()*data.height();j++){  //for reading the half image in img array
			if(count==data.width()/2){
			flag==1-flag;	
			count=0;
		}
		if(flag==1)
			img[j++]=temp[i]; 
		count++;
	}
 
	glDrawPixels(data.width(),data.height(),GL_RGBA,GL_UNSIGNED_BYTE,img);
 
}
 
 
void Radha::resizeGL(int w,int h){
	glViewport(0,0,w,h);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glOrtho(0,w,0,h,-1,1);
	glMatrixMode(GL_MODELVIEW);
 
}
 
int main(int argc,char** argv){
	QApplication app(argc,argv);
	Radha pw(argv[1]);
	pw.showFullScreen();
	return app.exec();
}

#include "qgl.h"
#include "qapplication.h"
#include "qimage.h"
#include "iostream.h"
#include "GL/gl.h"
class Radha : public QGLWidget
{
	public:
		Radha(const QString &filename,QWidget *parent=0);
		void paintGL();
		void resizeGL(int w,int h);
		void divide();
	protected:
		QImage data,gldata;
};

Radha::Radha(const QString &filename,QWidget *parent):QGLWidget(parent){
	data.load(filename);
	gldata=QGLWidget::convertToGLFormat(data);
	resize(data.size());
	
}

void Radha::paintGL(){
	int k,i,j,count=0,flag=1;	
<PROBLEM>	
	uchar *temp;
	uchar *img;
	temp=gldata.bits();
		
	for(j=0;j<data.width()*data.height();j++){  //for reading the half image in img array
			if(count==data.width()/2){
			flag==1-flag;	
			count=0;
		}
		if(flag==1)
			img[j++]=temp[i]; 
		count++;
	}

	glDrawPixels(data.width(),data.height(),GL_RGBA,GL_UNSIGNED_BYTE,img);

}


void Radha::resizeGL(int w,int h){
	glViewport(0,0,w,h);
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	glOrtho(0,w,0,h,-1,1);
	glMatrixMode(GL_MODELVIEW);
	
}

int main(int argc,char** argv){
	QApplication app(argc,argv);
	Radha pw(argv[1]);
	pw.showFullScreen();
	return app.exec();
}

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