thermometer* c = new centigrade();
  thermometer* f = new fahrenheit();
  
  displayer* cd = new displayer("centigrade");
  displayer* fd = new displayer("fahrenheit");
  
  prompter* cp = new prompter("enter centigrade value");
  prompter* fp = new prompter("enter fahrenheit value");
  
  show* sc = new show(c,cd);
  show* sf = new show(f,fd);
  
  update* uc = new update(c,cp);
  update* uf = new update(f,fp);
  

slide: Installing the objects