抽象方法---猫与狗的实例

abstract class Animal{
abstract void speak();
}
class dog extends Animal{
void speak(){
System.out.println("狗：旺旺");
}
}
class cat extends Animal{
void speak(){
System.out.println("猫：喵喵");
}
}
public class DogCat{
public static void main(String args[]){
dog d1=new dog();
d1.speak();
cat c1=new cat();
c1.speak();
}
}