Hello everyone! I am beginner in OpenGL and I am having problems making an object rotate using the glutTimerFunc. I expect to see this cube rotating around the vertical axis, which passes through its center, but I can't see it rotate. My code is

Code :
#include <stdio.h>
#include <stdlib.h>
#include <glut.h>
#include <math.h>
 
#define pi 3.14159265
 
typedef GLfloat point3d[3];
point3d p0={-1,-1,-13}, p1={1,-1,-13}, p2={-1,1,-13}, p3={1,1,-13}; 
point3d p4={-1,-1,-15}, p5={1,-1,-15}, p6={-1,1,-15}, p7={1,1,-15};
int  r=1, theta=0, phi=0, delay=300, angle; //delay in msec
float xe, ye, ze;
 
void InitWindow()
{
	glEnable(GL_DEPTH_TEST);
	glClearColor(0.9,0.9,0.9,0);  
	glMatrixMode(GL_PROJECTION);
	glFrustum(-2,2,-2,2,10,1500);
//	glOrtho(-4,5,-3,5,-13,14);
 
	glEnable(GL_LIGHTING);
	glEnable(GL_COLOR_MATERIAL);
	GLfloat lighting[]={0.7,0.7,0.7,1};
	GLfloat lightPos[] = {2, 2, -14, 1};
	glLightfv(GL_LIGHT0,GL_DIFFUSE,lighting);
	glLightfv(GL_LIGHT0, GL_POSITION, lightPos);
	glColorMaterial(GL_FRONT_AND_BACK,GL_AMBIENT_AND_DIFFUSE);
 
	glMatrixMode(GL_MODELVIEW);
}
 
void Cube()
{
	glBegin(GL_QUADS); //left cube
		glColor3f(0.3,0.3,0.9);//blue
		glVertex3fv(p0); glVertex3fv(p1); glVertex3fv(p3); glVertex3fv(p2);  //front
		glColor3f(0.1,0.6,0.9);
		glVertex3fv(p1); glVertex3fv(p5); glVertex3fv(p7); glVertex3fv(p3);  //right
		glColor3f(0,0.3,0.9);
		glVertex3fv(p5); glVertex3fv(p4); glVertex3fv(p6); glVertex3fv(p7);  //back
		glColor3f(0.3,0,0.9);
		glVertex3fv(p4); glVertex3fv(p0); glVertex3fv(p2); glVertex3fv(p6);  //left
		glColor3f(0.3,0.3,0);
		glVertex3fv(p2); glVertex3fv(p3); glVertex3fv(p7); glVertex3fv(p6);  //top
		glColor3f(1,0.3,1);
		glVertex3fv(p1); glVertex3fv(p0); glVertex3fv(p4); glVertex3fv(p5);  //bottom
	glEnd();
}
 
void Display(void)
{
	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);  
	glLoadIdentity();
//	xe=r*cos(theta*pi/180.)*sin(phi*pi/180.)+0.5; //(xe,ye,ze) the direction of vision
//	ye=r*sin(theta*pi/180.)*sin(phi*pi/180.); // (0.5,0,0) the focus point
//	ze=r*cos(phi*pi/180.);
	gluLookAt(0,0,0,0.,0.,-14.,0.,1.,0.);// (0,1,0) the angle of the camera
	Cube();
	glRotatef(angle,0,1,0);
	glutSwapBuffers();
}
 
void StepRot(int n)  //the "glutTimerFunc"
{
	n++;
	angle+=5;
	printf("n",n);
	glutPostRedisplay();
	glutTimerFunc(delay,StepRot,n);
	if(n<100)  glutTimerFunc(delay,StepRot,n);
}
 
void main(int argc, char **argv)
{
	glutInit(&argc, argv);
	glutInitDisplayMode(GLUT_DOUBLE|GLUT_RGB|GLUT_DEPTH);   
	glutInitWindowPosition(200,100);
	glutInitWindowSize(400,400);
	glutCreateWindow("3D-cubes rotating in light");
	InitWindow();      
 
	glutDisplayFunc(Display);  
	glutTimerFunc(delay,StepRot,0);
	glutMainLoop();
}

Thanks a lot for every help!