#include <GL/gl.h>
#include <GL/glut.h>
#include<stdio.h>
float x1,y1,x2,y2,m,i,j;
int dx=0,dy=0;
void display(void)
{

glClear (GL_COLOR_BUFFER_BIT);

glEnd();

glColor3f (0.0, 1.0, 0.0);
glBegin(GL_POINTS);
if(dx==1){
    for(i=x1,j=y1;i<=x2,j<=y2;i=i+1,j=j+m){
glVertex3f (i, j, 0.0);
    }


}
else if(dy==1){
    for(i=x1,j=y1;i<=x2,j<=y2;i=(i+(1/m)),j=j+1){
glVertex3f (i, j, 0.0);

}
}
else if(dx==(-1)){
    for(i=x1,j=y1;i>=x2,j>=y2;i=i-1,j=j-m){
glVertex3f (i, j, 0.0);
    }
}
else{
    for(i=x1,j=y1;i>=x2,j>=y2;i=(-(1/m)+i),j=j-1){
glVertex3f (i, j, 0.0);
}
}
glEnd();



glFlush ();
}
void init (void)
{

glClearColor (0.0, 0.0, 0.0, 0.0);

glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-50, 50, -50, 50, -50, 50);
}



int main(int argc, char** argv)
{

printf("Enter the value of x1 : ");
scanf("%f",&x1);
printf("Enter the value of y1 : ");
scanf("%f",&y1);
printf("Enter the value of x2 : ");
scanf("%f",&x2);
printf("Enter the value of y2 : ");
scanf("%f",&y2);
    m=(y2-y1)/(x2-x1);
    if(m<=1){
            if((x1>x2)&&(y1>y2)){
                dx=-1;
            }
            else{
        dx=1;
            }
    }
    else{
            if(x1>x2&&y1>y2){
                dy=-1;
            }
            else{
        dy=1;
            }
    }

glutInit(&argc, argv);
glutInitDisplayMode (GLUT_SINGLE | GLUT_RGB);
glutInitWindowSize (500, 500);
glutInitWindowPosition (100, 100);
glutCreateWindow ("hello");
init ();
glutDisplayFunc(display);
glutMainLoop();
return 0;
}