Using OpenGL: Drawing a rectangle or Square

#include <i:\windows\system32\glut.h>
#include <i:\windows\system32\glu.h>
#include <i:\windows\system32\gl.h>
#include <windows.h>

void Display(void)
{
glClear(GL_COLOR_BUFFER_BIT);
//glRectf(-5.0,5.0,5.0,-5.0);
glRectf(-7.0,7.0,7.0,-7.0);

glutSwapBuffers();
}

void init(void)
{
glClearColor(0.0,0.0,0.0,0.0);
//glColour3f(0.0,0.0,1.0);
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-10.0,10.0,-10.0,10.0,-10.0,10.0);
}

int main (int argc, char **argv)
{
glutInit(&argc, argv);
glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);  //For animations you should use double buffering
glutInitWindowSize(300,300);
glutInitWindowPosition(100,100);
glutCreateWindow("Rectangle Example");
glPolygonMode(GL_FRONT_AND_BACK,GL_LINE);
init();
glutDisplayFunc(Display);
glutMainLoop();
return 0;
}