Javase—多态习题

/**
 * 【练习题】1.多态练习
   1.定义一个Animal父类，方法有eat();
	2.定义三个子类；
			Cat,Dog,Eagle;
			每个子类增加新的方法,并重写eat();
	3.利用多态性
			定义一个Animal类型的变量a，并将不同子类的实例赋给a；
			调用eat();观察结果后，并理解多态
	4.思考，如果a的引用指向一个Cat,如何调用Cat的新增方法；
 */

package com.Oracle.oop4;

public class Animal {
	
	public void eat() {
		System.out.println("吃吃");
	}

}

package com.Oracle.oop4;

public class Cat extends Animal{

	@Override
	public void eat() {
		System.out.println("咦，这是谁掉落的小鱼干(= =+)");
	}

	public void scorn() {
		System.out.println("蔑视尔等凡人");
	}

}

package com.Oracle.oop4;

public class Dog extends Animal {

	public void eat() {
		System.out.println("汪汪汪，我什么都吃哒~");
	}
	
	public void adhere() {
		System.out.println("不粘人的狗不是好狗");
	}
}

package com.Oracle.oop4;

public class Eagle extends Animal {

	public void eat() {
		System.out.println("作为一只鹰，吃肉不是理所当然的吗");
	}
	public void fly() {
		System.out.println("想飞上天，和太阳肩并肩");
	}

}

package com.Oracle.oop4;

public class Polymorphic1 {

	public static void main(String[] args) {
		Animal a=new Cat();
		a.eat();
		a=new Dog();
		a.eat();
		a=new Eagle();
		a.eat();
		if(a instanceof Cat) {
			Cat c=(Cat)a;
			c.scorn();
		}else if(a instanceof Dog) {
			Dog d=(Dog)a;
			d.adhere();
		}else if(a instanceof Eagle) {
			Eagle e=(Eagle)a;
			e.fly();
		}
	}

}

 /**
 * 【练习题】2.多态练习
定义一个Animal类，方法有sing方法，定义这个类的三个子类（Dog,Cat,Bird），分别重写这个方法。利用多态，定义一个Animal类型的对象，
Animal a;分别引用三个子类的对象，调用sing方法。为每个子类，增加额外的方法。通过此例，练习upCast,downCast,及instanceof操作符。
 */


package com.Oracle.oop4;

public class Animal2 {
	public void sing() {
		System.out.println("啦啦，唱歌");
	}

}

package com.Oracle.oop4;

public class Dog2 extends Animal2{

	@Override
	public void sing() {
		System.out.println("我只会说：汪汪，会让你更旺哦");
	}
	public void adhere() {
		System.out.println("不粘人的狗不是好狗");
	}

}

package com.Oracle.oop4;

public class Cat2 extends Animal2 {

	@Override
	public void sing() {
		System.out.println("喵喵，陪我玩啊");
	}
	public void scorn() {
		System.out.println("蔑视尔等凡人");
	}
}

package com.Oracle.oop4;

public class Bird2 extends Animal2{

	@Override
	public void sing() {
		System.out.println("你去打听，十里八村数我小鸟唱歌最好听");
	}
	public void fly() {
		System.out.println("想飞上天，和太阳肩并肩");
	}
}

package com.Oracle.oop4;

public class Polymorphic2 {

	public static void main(String[] args) {
		Animal2 a=new Cat2();
		a.sing();
		a=new Dog2();
		a.sing();
		a=new Bird2();
		a.sing();
		if(a instanceof Cat2) {
			Cat2 c=(Cat2)a;
			c.scorn();
		}else if(a instanceof Dog2) {
			Dog2 d=(Dog2)a;
			d.adhere();
		}else if(a instanceof Bird2) {
			Bird2 b=(Bird2)a;
			b.fly();
		}
	}
}

/**
 * 【练习题】3.多态练习
模拟天天酷跑游戏；
定义一个（宠物）Pet类，类中有属性name,方法是follow(跟随)；再定义三个子类，Cat,Dog,Eagle,分别重写follow方法；
   再定义一个Hero类，这个类中有两个属性name和Pet类型的pet,一个方法run(),再定义两个构造方法，Hero(String name,);
   Hero(String name,Pet pet);
 run()方法的代码是Hero跑，并且他的宠物也跟着跑；
编写测试类来操作Hero
 */

package com.Oracle.oop4_2;

public class Pet {
	String name;
	public void follow() {
		System.out.println(this.name+"一直跟随着您呦~");
	}
}

package com.Oracle.oop4_2;

public class Hero {
	String name;
	Pet pet;
	
	public Hero(String name) {
		this.name=name;
	}
	public Hero(String name, Pet pet) {
		this.name = name;
		this.pet = pet;
	}
	public void run() {
		System.out.println("您的英雄 "+this.name+" 在跑,并且您的宠物 "+this.pet.name+"也跟着您的英雄跑");
	}
}

package com.Oracle.oop4_2;

public class Cat extends Pet {
	public void follow() {
		System.out.println(this.name+"可以萌化凶狠的对手");
	}
}

package com.Oracle.oop4_2;

public class Dog extends Pet{
	public void follow() {
		System.out.println(this.name+"保护您一路前行");
	}
}

package com.Oracle.oop4_2;

public class Eagle extends Pet{
	public void follow() {
		System.out.println(this.name+"飞上了天，并和您肩并肩");
	}
}

package com.Oracle.oop4_2;

public class Polymorphic3 {

	public static void main(String[] args) {
		Pet c=new Cat();
		c.name="蓝胖子";
		Hero h=new Hero("盖伦",c);
		h.run();
	}
}

/**
 * 定义一个测试类Test，编写equalsArea方法测试两个对象的面积是否相等（注意方法的参数类型，利用动态绑定技术），
 * 编写displayGeometricObject方法显示对象的面积（注意方法的参数类型，利用动态绑定技术）。
 */

package com.Oracle.oop4_2;

public class GeometricObject {
	static final double PI=3.1415926;
	String color;
	double weight;
	public String getColor() {
		return color;
	}
	public void setColor(String color) {
		this.color = color;
	}
	public double getWeight() {
		return weight;
	}
	public void setWeight(double weight) {
		this.weight = weight;
	}
	public GeometricObject(String color, double weight) {
		this.color = color;
		this.weight = weight;
	}
	public double findArea() {
		double a=0;
		return a;
	}
	public boolean equalsArea(GeometricObject c,GeometricObject m) {
		if(c.findArea()==m.findArea()) {
			return true;
		}
		return false;
	}
	public void displayGeometricObject(GeometricObject g) {
		System.out.println("该形状的面积为："+g.findArea());
	}
}

package com.Oracle.oop4_2;

public class MyRectangle extends GeometricObject {
	double width;
	double height;
	public double getWidth() {
		return width;
	}
	public void setWidth(double width) {
		this.width = width;
	}
	public double getHeight() {
		return height;
	}
	public void setHeight(double height) {
		this.height = height;
	}
	public MyRectangle(double width,double height,String color,double weight) {
		super(color,weight);
		this.width=width;
		this.height=height;
	}
	@Override
	public double findArea() {
		double s=width*height;
		return s;
	}
}

package com.Oracle.oop4_2;

public class Circle extends GeometricObject{
//	static final double PI=3.1415926;
	double radius;
	public double getRadius() {
		return radius;
	}
	public void setRadius(double radius) {
		this.radius = radius;
	}
	public Circle(double radius,String color,double weight) {
		super(color,weight);
		this.radius=radius;
	}
	public double findArea() {
		double s=GeometricObject.PI*radius*radius;
		return s;
	}
}

package com.Oracle.oop4_2;

public class Polymorphic4 {

	public static void main(String[] args) {
		GeometricObject g1=new Circle(5.2,"blue",4.3);
		GeometricObject g2=new MyRectangle(8.7,9.6,"yellow",5.1);
		System.out.println(g1.equalsArea(g1, g2));
		g1.displayGeometricObject(g1);
		g2.displayGeometricObject(g2);
		
	}

}