#include <windows.h>   // use as needed for your system
#include <gl/Gl.h>
#include <gl/glut.h>
//<<<<<<<<<<<<<<<<<<<<<<< myInit >>>>>>>>>>>>>>>>>>>>
 void myInit(void)
 {
    glClearColor(1.0,1.0,1.0,0.0);       // set white background color
    glColor3f(0.0f, 0.0f, 0.0f);          // set the drawing color 
 	glPointSize(4.0);		       // a ‘dot’ is 4 by 4 pixels
	glMatrixMode(GL_PROJECTION); 
	glLoadIdentity();
	gluOrtho2D(0.0, 640.0, 0.0, 480.0);
}
//<<<<<<<<<<<<<<<<<<<<<<<< myDisplay >>>>>>>>>>>>>>>>>
void myDisplay(void)
{
	glClear(GL_COLOR_BUFFER_BIT);     // clear the screen 
	glBegin(GL_POINTS);
		glVertex2i(100, 50);         // draw three points
		glVertex2i(100, 130);
		glVertex2i(150, 130);
	glEnd();	
	glFlush();		                 // send all output to display 
}

//<<<<<<<<<<<<<<<<<<<<<<<< main >>>>>>>>>>>>>>>>>>>>>>
void main(int argc, char** argv)
{
	glutInit(&argc, argv);          // initialize the toolkit
	glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB); // set display mode
	glutInitWindowSize(640,480);     // set window size
	glutInitWindowPosition(100, 150); // set window position on screen
	glutCreateWindow("my first attempt"); // open the screen window
	glutDisplayFunc(myDisplay);     // register redraw function
	myInit();                   
	glutMainLoop(); 		     // go into a perpetual loop
}