Display an iterative process

Hi,

First of all, I’m new at OpenGL/glut. I’m using C++ and GLUT to display 2D-meshes.
How can I update the display in order to show an iterative process? (I’m not really sure how to give a better explamation)

void screen(){   //displays all the edges, each defined by two nodes n1 and n2
    ...stuff...
    glClear(GL_COLOR_BUFFER_BIT);
    glLineWidth(2.0);
    glBegin(GL_LINES);
    ...stuff...
    glColor3f(1.0,0.5,0.0);
    glVertex2d(n1[0],n1[1]);
    glVertex2d(n2[0],n2[1]);
    glEnd();
    glFlush();
}

int main(int argc, char *argv[]){ //main function

    ...stuff...
    for(int i=0;i<50;i++)
        nodes.laplacian_smooth(edges,adjmat,tot_nodes);  //This is my iterative process, it changes the coordinates of the nodes

    glutInit(&argc, argv);
    glutInitWindowSize(600,600);
    glutInitWindowPosition(10,10);
    glutInitDisplayMode(GLUT_RGB | GLUT_SINGLE);
    glutCreateWindow("LS");
    scrset();
    glutDisplayFunc(screen);
    glutMainLoop();
    return EXIT_SUCCESS;

}

Thanks.