title: how to slow down the execution of a code in C?
body: <p>I am self-learning openGL in C on a linux machine. Here is my basic code for drawing a circle using a loop. I would like to slow down the execution of this program so that I can see the formation of the circle point by point. (hope I am able to convey properly what  I mean).</p>
  
  <pre><code>#include &lt;GL/glut.h&gt;    // Header File For The GLUT Library
  #include&lt;math.h&gt;
  
  void main (int argc, char*argv[])
  {
      float y, x=-0.75;
  
      glutInit(&amp;argc, argv);
      glutInitDisplayMode (GLUT_RGBA | GLUT_DEPTH);
      glutInitWindowPosition(200,150);
      glutInitWindowSize(500,500);
      glutCreateWindow (argv[0]);
  
      glClearColor (0.0, 0.0, 0.0, 0.0);  // choosing the background color
      glClear (GL_COLOR_BUFFER_BIT);      // setting the color buffer to background color
      glColor3f(1,1,1);
      glPointSize(2);
  
      for (x=-0.75;x &lt;= 0.75; x=x+0.005){
          y = sqrt(0.5625 -(x*x));
  
          glBegin(GL_POINTS);
              glVertex2f(x,y);
              glVertex2f(x,-y);
          glEnd();
  
      }
  
  
  
      glFlush();
  
      glutMainLoop();
  
  }
  </code></pre>