Java——抽象类

publicabstractclass类名();
publicabstractvoideat();

packageabs;
publicabstractclassAnimal {
privateintage=20;
privatefinalStringcity="UK";
publicAnimal(){}
publicAnimal(intage){
System.out.println(age);
    }
publicvoidshow(){
age=40;
System.out.println(age);
System.out.println(city);
    }
publicabstractvoideat();
}

packageabs;
publicclassCatextendsAnimal{
@Overridepublicvoideat() {
System.out.println("fish");
    }
}

packageabs;
publicclassDemo {
publicstaticvoidmain(String[] args) {
Animala=newCat();
a.eat();
a.show();
    }
}