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1、例 5-1class Fatherprivate int moneyDollar=300;int moneyHK=200;int add(int x,int y)return x+y;class Son extends Fatherint moneyRMB=800;public void changMoneyHK(int x)moneyHK=x;public void changMoneyRMB(int x)moneyRMB=x;int subs(int x,int y)return x-y;class GrandSon extends Sonint multi(int x,int y)ret
2、urn x*y;public class Example5_1 public static void main(String args) / TODO Auto-generated method stubint a=5,b=3;Son son=new Son();GrandSon sunzi=new GrandSon();son.changMoneyHK(666);son.changMoneyRMB(5000);System.out.println(儿子的港币是继承的属性，当前的 值是： +son.moneyHK);System.out.println(儿子的人民币是新增的属性，当前的 值是：
3、 +son.moneyRMB);System.out.printf(减法是儿子新增的功能,%d-%d 等于%dn,a ,b,son.subs(a, b);System.out.printf(加法是儿子继承的功能,%d+%d 等于%dn,a ,b,son.subs(a, b);System.out.println(孙子的港币和人民币都是 继承的属性，当前的值是： );System.out.println(港币 +sunzi.moneyHK+人民币： +sunzi.moneyRMB);System.out.printf(乘法是孙子新增的功能，%d*%d 等于%dn,a,b,sunzi.multi(
4、a,b) ;System.out.printf(加法是孙子继承的功能，%d+%d 等于%dn,a,b,sunzi.add(a,b);System.out.printf(减法是孙子继承的功能，%d-%d 等于%dn,a,b,sunzi.subs(a,b);例 5-2class Aprivate int x=10;protected int y=20;void f()y=y+x;System.out.printf(x=%d,y=%dn,x,y);class B extends Avoid g()y=y+1;System.out.printf(y=%dn,y);public class Exampl
5、e5_2 public static void main(String args) / TODO Auto-generated method stubB b=new B();b.g();b.f();b.g();例 5-3class Apublic double y=11.456789;public void f()y=y+1;System.out.printf(y 是 double 型的变量名，y=%fn, y);class B extends Aint y=0;public void g()y=y+100;System.out.printf(y 是 int 型的变量名，y=%dn,y );p
6、ublic class Example5_3 public static void main(String args) / TODO Auto-generated method stubB b=new B();b.y=200;b.g();b.f();例 5-4class Aprotected double x=8.0,y=0.888888;public void speak()System.out.println(我喜欢 NBA);public void cry()y=x+y;System.out.printf(y=%fn,y);class B extends Aint y=100,z;pub
7、lic void speak()z=2*y;System.out.println(I love This Game);System.out.printf(y=%d,z=%d,y,z);public class Example5_4 public static void main(String args) / TODO Auto-generated method stubB b=new B();b.cry();b.speak();例 5-5class Apublic int f(int x,int y)return x+y;class B extends Apublic int f(byte x
8、,int y)return x*y;public class Example5_5 public static void main(String args) / TODO Auto-generated method stubint z=0;B b=new B();z=b.f(10, 10);System.out.println(z);z=b.f(byte)10,10);System.out.println(z);例 5-6class Aint x,y;A()x=100;y=200;A(int x,int y)this.x=x;this.y=y;class B extends Aint z;B(
9、int x,int y)super(x,y);z=300;B()super();z=800;public void f()System.out.printf(x=%d,y=%d,z=%dn,x,y,z);public class Example5_6 public static void main(String args) / TODO Auto-generated method stubB b1=new B(10,20);b1.f();B b2=new B();b2.f();例 5-8class Adouble n;int m;void f()System.out.printf(子类继承方法
10、 f(),n=%f.m=%dn,n,m);void g()System.out.printf(你好，n=%f,m=%dn,n, m);class B extends Aint n=12;void g()System.out.printf(子类重写方法 g(),n=%d,m=%dn,n,m);void cry()System.out.printf(子类新增方法,n=%d,m=%dn,n ,m);public class Example5_8 public static void main(String args) / TODO Auto-generated method stubA a;a=ne
11、w B();a.n=0.618;a.m=200;a.f();a.g();B b=(B)a;b.n=555;b.cry();例 5-9class Animalvoid cry()class Dog extends Animalvoid cry()System.out.println(Wamg!Wang!.);class Cat extends Animalvoid cry()System.out.println(miaomiao.);public class Example5_9 public static void main(String args) / TODO Auto-generated
12、 method stubAnimal animal;animal=new Dog();animal.cry();animal=new Cat();animal.cry();例 5-11interface Computablefinal int MAX=100;int f(int x);public abstract int g(int x,int y);class A implements Computablepublic int f(int x)return x*x;public int g(int x,int y)return x+y;class B implements Computab
13、lepublic int f(int x)return x*x*x;public int g(int x,int y)return x*y;public class Example5_11 public static void main(String args) / TODO Auto-generated method stubA a=new A();B b=new B();System.out.println(a.MAX);System.out.println(+a.f(10)+a.g(12, 6);System.out.println(b.MAX);System.out.println(+
14、b.f(10)+b.g(29, 2);例 5-12interface ShowMessagevoid showTradeMark();class TV implements ShowMessagepublic void showTradeMark()System.out.println(我是电视机 );class PC implements ShowMessagepublic void showTradeMark()System.out.println(我是电脑 );public class Example5_12 public static void main(String args) /
15、TODO Auto-generated method stubShowMessage sm;sm=new TV();sm.showTradeMark();sm=new PC();sm.showTradeMark();例 5-13interface Showvoid show();class A implements Showpublic void show()System.out.println(I love This Game);class B implements Showpublic void show()System.out.println(我喜欢看 NBA);class Cpublic void f(Show s)s.show();public class Example5_13 public static void main(String args) / TODO Auto-generated method stubC c=new C();c.f(new A();c.f(new B
