MOVING CIRCLE IN OPENGL

#include <GL/glut.h>
#define true 1
#define false 0
static spinning = false;
static const int FPS = 60;
float flag=1;
static GLfloat currentAngleOfRotation = 45.0;

void reshape(GLint w, GLint h) {

  GLfloat aspect = (GLfloat)w / (GLfloat)h;
  glMatrixMode(GL_PROJECTION);
  glLoadIdentity();
  if (w <= h) {
    glOrtho(-50.0, 50.0, -50.0/aspect, 50.0/aspect, -1.0, 1.0);
//     f1=1;
  } else {
    glOrtho(-50.0*aspect, 50.0*aspect, -50.0, 50.0, -1.0, 1.0);
 //    f2=1;
  }
}

void display() {
   float angle,x,y;
   int i;
  glClear(GL_COLOR_BUFFER_BIT);
  glMatrixMode(GL_MODELVIEW);
  glLoadIdentity();
  glRotatef(currentAngleOfRotation, 0.0, 0.0, 1.0);
  glScalef(10.0,10.0,10.0);
//  printf("f1=%d f2=%d",f1,f2);
    glBegin(GL_TRIANGLE_STRIP);
  glVertex2f(1.0,0.0);
  glVertex2f(2.0,0.0);
  glVertex2f(2,0.5);
  glEnd();
   glBegin(GL_TRIANGLE_STRIP);
  glVertex2f(-1.0,0.0);
  glVertex2f(-2.0,0.0);
  glVertex2f(-2,-0.5);
  glEnd();
   glBegin(GL_TRIANGLE_STRIP);
  glVertex2f(0.0,-1.0);
  glVertex2f(0.0,-2.0);
  glVertex2f(0.5,-2.0);
  glEnd();
   glBegin(GL_TRIANGLE_STRIP);
  glVertex2f(0.0,1.0);
  glVertex2f(0.0,2.0);
  glVertex2f(-0.5,2.0);
  glEnd();
  glBegin(GL_POINTS);
   for(i=0;i<360;i++)
   {
    angle=2*3.14*i/360;
    x=cos(angle);
    y=sin(angle);
    glVertex2f(x,y);
   }

  glEnd();
  glFlush();
  glutSwapBuffers();
}

void timer(int v)
 {
  if (spinning)
   {
 
 
    currentAngleOfRotation += 2.0;
      if(currentAngleOfRotation==360.0)
      {
   
  currentAngleOfRotation = -360.0;
     
 }
     glutPostRedisplay();
  }
  glutTimerFunc(1000/FPS, timer, v);
}

void mouse(int button, int state, int x, int y) {
  if (button == GLUT_LEFT_BUTTON && state == GLUT_DOWN) {
    spinning = true;
  } else if (button == GLUT_RIGHT_BUTTON && state == GLUT_DOWN) {
    spinning = false;
  }
}

int main(int argc, char** argv) {
  glutInit(&argc, argv);
  glutInitDisplayMode(GLUT_DOUBLE | GLUT_RGB);
  glutInitWindowPosition(80, 80);
  glutInitWindowSize(800, 500);
  glutCreateWindow("Spinning Square");
  glutReshapeFunc(reshape);
  glutDisplayFunc(display);
  glutTimerFunc(100, timer, 0);
  glutMouseFunc(mouse);
  glutMainLoop();
}

CIRCLE USING OPENGL

#include<GL/glu.h>
#include<GL/glut.h>
#include<GL/gl.h>
#include<math.h>
void display()
{
     glClear(GL_COLOR_BUFFER_BIT);
     glColor3f(1.0,0.0,0.0);
    // glColor3f(1.0,0.0,0.0);
   
     glPointSize(6.0);
     //glPointSize(6.0);
 
   
     int i;
     double angle,x,y;
     float PI=3.14;
     glBegin(GL_LINES);  
                            for(i=0;i<=300;i++)
                            {
                              angle=2*PI*i/300;
                              x=0.5*cos(angle);
                              y=0.5*sin(angle);
                              glVertex2d(x,y);
                            }
     glEnd();
                         
     glFlush();
}


int main(int argc,char **argv)
{
    glutInit(&argc,argv);
    glutInitWindowSize(500,500);
    glutInitWindowPosition(100,100);
    glutInitDisplayMode(GLUT_RGB|GLUT_SINGLE);
    glutCreateWindow("Going for a SMILEY :-)");
    glutDisplayFunc(display);
 
    glutMainLoop();
}