OpenGL show object on the screen - c++

Question

I just started learning OpenGL so I have problem with showing the object on the screen.
Display() contains this object and I want to show this one by glutDisplayFunc(Display); but it's not working, I have only grey screen after compiling. (Yeah, this object is wheel)
#include "stdafx.h"
#include <math.h>
#include <GL/freeglut.h>
GLint Width = 1024, Height = 640;
const int CubeSize = 500;
void Display (void) {
glClearColor (0.7, 0.7, 0.7, 1);
glClear (GL_COLOR_BUFFER_BIT);
glColor3ub (255, 200, 200);
int iTimeElapsed = glutGet(GLUT_ELAPSED_TIME);
float fRevolveScale1 = 0.2f;
float fRevolveScale2 = 0.4f;
long i;
// clear all pixels
glClear(GL_COLOR_BUFFER_BIT);
// push temp state
glPushMatrix();
// translate to center
glTranslatef(0.5f, 0.5f, 0.0);
// rotate around pivot
glRotatef(iTimeElapsed * fRevolveScale1, 0.0, 0.0, 1.0);
// translate to planet location
glTranslatef(0.25f, 0.25f, 0.0);
glRotatef(iTimeElapsed * fRevolveScale2, 0.0, 0.0, 1.0);
glColor3f(0.129412f, 0.129412f, 0.129412f);
glutSolidSphere(0.1f, 16, 16);
// five bolts, step 72 degree (72*5=360 degree)
glColor3f(1.0, 1.0, 1.0);
for (i = 0; i<5; ++i)
{
glPushMatrix();
glRotatef(72.0f*i, 0.0, 0.0, 1.0); // rotate coordinate 72 degree
glTranslatef(0.04f, 0.0, 0.0);// translate on the rotated coordinate
glutSolidSphere(0.01f, 16, 16);
glPopMatrix();
}
glTranslatef(0.0f, 0.0f, 0.0f);// translate on the rotated coordinate
glutSolidSphere(0.01, 16, 16);
// pop temp state
glPopMatrix();
glFlush();
glutPostRedisplay();
glFinish ();
}
void Reshape(GLint w, GLint h) {
Width = w, Height = h;
glViewport (0, 0, w, h);
glMatrixMode(GL_PROJECTION);
glLoadIdentity ();
glOrtho (0, w, 0, h, -1.0, 1.0);
glMatrixMode(GL_MODELVIEW);
glLoadIdentity ();
}
void Keyboard(unsigned char key, int x, int y) {
const char ESCAPE = '\033 ';
if (key == ESCAPE) exit (0);
}
void main(int argc, char *argv []) {
glutInit(&argc, argv);
glutInitDisplayMode (GLUT_RGB);
glutInitWindowSize (Width, Height);
glutCreateWindow("E X A M P L E");
glutDisplayFunc(Display);
glutReshapeFunc(Reshape);
glutKeyboardFunc(Keyboard);
glutMainLoop ();
}