$/*$File Proj$12.$java

The purpose of this assignment is to assess the student's

ability to write programs involving runtime polymorphism

based on interface inheritance.

$***********************************************************/$

$//$ Student must not modify the code in this file. $//$

class Proj$12\{$

public static void main$($String$[]$ args$)\{$

Proj$12$Runner var $=$ new Proj$12$Runner$()$;

System.out.println$("=====$This line is required$=====")$;

Animal cat $=$ new Cat$()$;

System.out.println$($cat$.$speak$())$;

Animal dog $=$ new Dog$()$;

System.out.println$($dog$.$speak$())$;

Animal cow $=$ new Cow$()$;

System.out.println$($cow$.$speak$())$;

$\}//$end main

$\}//$end class Proj$12$

$//===============================================//$

interface Animal$\{$

public String speak$()$;

public void sleep$()$;

public int run$()$;

$\}//$end interface