This program will draw a 3D cylinder using OpenGL 2.1 API

OpenGL 2.1 Draw3D Cylinder

/*------------------------------------------------------------------+
 |                                                                  |
 |    This program will draw a 3D cylinder using OpenGL 2.1 API     |
 |                                                                  |
 |        Language: C89 strict                                      |
 |        Compiler: GNU GCC 4.8.3                                   |
 |                                                                  |
 |        Tested on Fedora 19 64-bit and Windows 7 64-bit,          |
 |        both works with no errors and no warnings :)              |
 |                                                                  |
 +------------------------------------------------------------------*/
#include <stdio.h>
#include <stdlib.h>
#include <GL/glut.h>
#include <math.h>

#define PI 3.1415927

/************************** draw_cylinder() **************************
 * This function will draw the cylinder
 *
 *   @parameter1: radius = The radius of cylinder
 *   @parameter2: height = Height of the cylinder
 *   @parameter3: R = Red value of the cylinder's color
 *   @parameter4: G = Green value of the cylinder's color
 *   @parameter5: B = Blue value of the cylinder's color
 *
 *   @return: Nothing
 */
void draw_cylinder(GLfloat radius,
                   GLfloat height,
                   GLubyte R,
                   GLubyte G,
                   GLubyte B)
{
    GLfloat x              = 0.0;
    GLfloat y              = 0.0;
    GLfloat angle          = 0.0;
    GLfloat angle_stepsize = 0.1;

    /** Draw the tube */
    glColor3ub(R-40,G-40,B-40);
    glBegin(GL_QUAD_STRIP);
    angle = 0.0;
        while( angle < 2*PI ) {
            x = radius * cos(angle);
            y = radius * sin(angle);
            glVertex3f(x, y , height);
            glVertex3f(x, y , 0.0);
            angle = angle + angle_stepsize;
        }
        glVertex3f(radius, 0.0, height);
        glVertex3f(radius, 0.0, 0.0);
    glEnd();

    /** Draw the circle on top of cylinder */
    glColor3ub(R,G,B);
    glBegin(GL_POLYGON);
    angle = 0.0;
        while( angle < 2*PI ) {
            x = radius * cos(angle);
            y = radius * sin(angle);
            glVertex3f(x, y , height);
            angle = angle + angle_stepsize;
        }
        glVertex3f(radius, 0.0, height);
    glEnd();
}

/**************************** display() ******************************
 * The glut callback function to draw the polygons on the screen.
 *
 *   @parameter1: Nothing
 *
 *   @return: Nothing
 */
void display(void)
{
    glClear(GL_COLOR_BUFFER_BIT);
    glLoadIdentity();

    glTranslatef(0.0,-0.4,-3.0);
    glRotatef(-40, 1.0, 0.0, 0.0);

    draw_cylinder(0.3, 1.0, 255, 160, 100);

    glFlush();
}

/**************************** reshape() ******************************
 * The glut callback function that responsible when the window is
 * resized.
 *
 *   @parameter1: width  = Current window's width
 *   @parameter2: height = Current window's height
 *
 *   @return: Nothing
 */
void reshape(int width, int height)
{
    if (width == 0 || height == 0) return;

    glMatrixMode(GL_PROJECTION);
    glLoadIdentity();
    gluPerspective(40.0, (GLdouble)width/(GLdouble)height,
                   0.5, 20.0);

    glMatrixMode(GL_MODELVIEW);
    glViewport(0, 0, width, height);
}

int main(int argc, char **argv)
{
    /** Initialize glut */
    glutInit(&argc, argv);
    glutInitDisplayMode(GLUT_SINGLE | GLUT_RGB);
    glutInitWindowSize(640,480);
    glutCreateWindow("Create Cylinder");
    glClearColor(0.0,0.0,0.0,0.0);
    glutDisplayFunc(display);
    glutReshapeFunc(reshape);

    glutMainLoop();

    return 0;
}

you should throw in the vert normal for the quad strip since its basically freeeeee!
glNormal3f(cos(angle),sin(angle),0);

is the very last "glVertex3f(radius, 0.0, height);" even necessary?

thank you @_@
great!!!

I am using GLFW and glew libraries for my class. the logic is the same but I dont know how to call it.