[تنبيه - عنوان غير مناسب : ]proplem

#include <iostream>
#include <stdlib.h>
#include <math.h>
#include <GL/glut.h>


using namespace std;


void setPixel(int x, int y)
{
    glBegin (GL_POINTS);
    glVertex2i (x,y);
    glEnd();
}


void draw_line(int x0,int y0,int xEnd,int yEnd)
{
        int dx = fabs(xEnd-x0) , dy = fabs(yEnd-y0);
        int p = 2 * dy - dx ;
        int TwoDy = 2 * dy , twoDyMinusDx = 2 *(dy-dx);
        int x,y;
cout<<p<<endl;

        if(x0 > xEnd){
        x=xEnd;
        y=yEnd;
        xEnd=x0;
        }
        else
        {
        x=x0;
        y=y0;
        }
        setPixel (x,y);
        while(x<xEnd){
        x++;
        if(p<0)
        p+= TwoDy ;
        else
        {
        y++;
        p+= twoDyMinusDx ;
        }
       setPixel(x,y);
        }
}

void init(void)
{

	glClearColor(1.0,1.0,1.0,0.0);
	glMatrixMode(GL_PROJECTION);
	gluOrtho2D(0.0,1100.0,0.0,700.0);
}

void winReshapeFcn(int newWidth, int newHeight)
{
	glMatrixMode(GL_PROJECTION);
	glLoadIdentity();
	gluOrtho2D(0.0,(GLdouble)newWidth,0.0,(GLdouble)newHeight);
	glClear(GL_COLOR_BUFFER_BIT);

}


int main(int argc,char** argv)
{int x2;
int y2; 
int x3; 
int y3;
        cout << "Please enter the start point (x0,y0) of the line:" << endl;
        cin >> x2;
        cin >> y2;
        cout <<"Please enter end point (x1,y1) of the line:"<< endl;
        cin >> x3;
        cin >> y3;

	glutInit(&argc,argv);
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
	glutInitWindowPosition(50,20);
	glutInitWindowSize(1100,700);
	glutCreateWindow("First OpenGL Program");

	init();
 	glutDisplayFunc(draw_line( x2, y2,x3,y3));
	glutReshapeFunc(winReshapeFcn);
	glutMainLoop();
	return 0;
}