java程序设计基础_陈国君版第五版_第八章例题

java程序设计基础_陈国君版第五版_第八章例题

class Person{private String name;private int age;public Person(){System.out.println("调用了个人类的构造方法Person()");}public void setNameAge(String name , int age){this.name = name ;this.age = age ;}public void show(){System.out.println("姓名："+name+"\t年龄："+age);}}class Student extends Person{private String department;public Student(){System.out.println("调用了学生类的构造方法Student()");}public void setDepartment(String dep){department =dep;System.out.println("我是"+department+"的学生");}}public class Main8_1 {public static void main(String[] args){Student stu =new Student();stu.setNameAge("张三",21);stu.show();stu.setDepartment("计算机系");}}

class Person2{private String name;private int age;public Person2(){System.out.println("调用了个人类的无参构造方法Person()");}public Person2(String name,int age){System.out.println("调用了个人类的有参构造方法");this.name =name;this.age = age;}public void show(){System.out.println("姓名："+name+"\t年龄："+age);}}class Student2 extends Person2{private String department;public Student2(){System.out.println("调用了学生类的无参构造方法Student()");}public Student2(String name , int age ,String dep){super(name,age);department = dep;System.out.println("我是"+department + "的学生");System.out.println("调用了学生类的有参构造方法Student(String name,int age ,String dep)");}}public class Main8_2 {public static void main(String[] args){Student2 stu =new Student2();Student2 stu2 =new Student2("李四",23,"信息系");stu.show();stu2.show();}}

class Person3{protected String name ;protected int age ;public Person3(){}public Person3(String name,int age){this.name = name;this.age = age;}protected void show(){System.out.println("姓名："+name+"\t年龄："+age);}}class Student3 extends Person3{private String department;int age = 20;public Student3 (String xm,String dep){name = xm ;department = dep;super.age = 25;System.out.println("子类Student中的成员变量 age ="+age);super.show();System.out.println("系别："+department);}}public class Main8_3 {public static void main(String[] args){Student3 stu = new Student3("李四","信息系");}}

class Person4{protected String name ;protected int age ;public Person4(String name,int age){this.name = name;this.age = age;}protected void show(){System.out.println("姓名："+name+"\t年龄："+age);}}class Student4 extends Person4{private String department;public Student4(String name , int age ,String dep){super(name,age);department = dep;}protected void show(){System.out.println("系别："+department);}}public class Main8_4 {public static void main(String[] args){Student4 stu = new Student4("老王",24,"电子");stu.show();}}

class Person5{protected String name ;protected int age ;public Person5(String name,int age){this.name = name;this.age = age;}protected void show(){System.out.println("姓名："+name+"\t年龄："+age);}}class Student5 extends Person5{private String department;public Student5(String name , int age ,String dep){super(name,age);department = dep;}protected void show(){System.out.println("系别："+department);}public void subShow(){System.out.println("我在子类中");}}public class Main8_5 {publicstatic void main(String[] args){Person5 per = new Student5("王涛",24,"电子");per.show();//per.subshow();}}

class AAA{static final double PI = 3.14;public final void show(){System.out.println("pi = "+PI);}}class BBB extends AAA{private int num = 100;/*public void show(){System.out.println("num = "+ num);}*/}public class Main8_6 {public static void main(String[] args){BBB ex = new BBB();ex.show();}}

class A{int a = 1;}public class Main8_7 {public static void main(String[] args){A obj1 = new A();A obj2 = new A();String s1,s2,s3 = "abc",s4 = "abc";s1 = new String("abc");s2 = new String("abc");System.out.println("s1.eauqls(s2)是"+(s1.equals(s2)));System.out.println("s1 == s3是"+(s1 == s3));System.out.println("s1.equals(s3)是"+(s1.equals(s3)));System.out.println("s3 == s4是"+(s3 == s4));System.out.println("s2.equals(s3)是"+(s2.equals(s3)));System.out.println("s1==s2是"+(s1 == s2));System.out.println("obj1 == obj2是"+(obj1 == obj2));System.out.println("obj1.equals(obj2)是"+(obj1.equals(obj2)));obj1 = obj2;System.out.println("obj1 = obj2后obj1 == obj2是"+(obj1==obj2));System.out.println("obj1 = obj2 后  obj1.equals(obj2) 是"+(obj1.equals(obj2)));}}

class Person1{protected String name;public Person1(String xm){name = xm;}}public class Main8_8 {public static void main(String [] args){Person1 per = new Person1("张三");Class obj = per.getClass();System.out.println("对象per 所属的类为:"+obj);System.out.println("对象per是否是接口："+obj.isInterface());}}

public class Main8_9{static int count = 0;protected String name;protected int age;public Main8_9(String n1,int a1){name = n1;age = a1;this.count++;}public String toString() {return this.name+" , "+this.age;}public void display(){System.out.print("本类名 = "+this.getClass().getName()+";");System.out.println("父类名 = "+this.getClass().getSuperclass().getName());System.out.print("Main8_9.count = "+this.count+" ");System.out.print("Student9.count = "+Student9.count+" ");Object obj = this;if(obj instanceof Student9)System.out.println(obj.toString() + "是Student9类对象");else if(obj instanceof Main8_9)System.out.println(obj.toString() + "是Main8_9类对象");}}class Student9 extends Main8_9{static int count = 0;protected  String dept;protected Student9(String n1,int a1,String d1){super(n1,a1);dept = d1;this.count++;}public String toString(){return super.toString() +","+dept;}public void display(){super.display();System.out.print("super.count = "+super.count);System.out.println("\t;this.count="+this.count);}public static void main(String[] args){Main8_9 per = new Main8_9("王永涛",23);per.display();Student9 stu = new Student9("张小三",22,"计算机系");stu.display();}}

abstract class Shape{protected String name;public Shape(String xm){name = xm;System.out.print("名称:"+name);}abstract public double getArea();abstract public double getLength();}class Circle extends Shape{private final double PI = 3.14;private double radius;public Circle(String shapeName,double r){super(shapeName);radius = r;}public double getArea(){return PI*radius*radius;}public double getLength(){return 2*PI*radius;}}class Rectangle extends Shape{private double width;private double height;public Rectangle(String shapeName,double width,double height){super(shapeName);this.width = width;this.height = height;}public double getArea(){return width * height;}public double getLength(){return 2*(width*height);}}public class Main8_10 {public static void main(String[] args){Shape rect = new Rectangle("长方形",6.5,10.3);System.out.print(";面积 = "+rect.getArea());System.out.println(";周长 ="+rect.getLength());Shape circle = new Circle("圆",10.2);System.out.println(";面积 = "+circle.getArea());System.out.println(";周长= "+circle.getLength());}}

interface IShape{final double PI = 3.14;abstract double getArea();abstract double getLength();}class Circle_11 implements IShape{double radius;public Circle_11(double r){radius = r;}public double getArea(){return PI*radius*radius;}public double getLength(){return 2*PI*radius;}}class Rectangle_11 implements IShape{private double width;private double height;public Rectangle_11(double width,double height){this.width = width;this.height = height;}public double getArea(){return width * height;}public double getLength(){return 2*(width + height);}}public class Main8_11 {public static void main(String[] args){IShape Circle_11 = new Circle_11(5.0);System.out.print("圆面积 ="+Circle_11.getArea());System.out.println(";周长 = "+Circle_11.getLength());Rectangle_11 rect = new Rectangle_11(6.5,10.8);System.out.print("矩形面积 ="+rect.getArea());System.out.println(";周长 = "+rect.getLength());}}

interface Face1{final double PI = 3.14;abstract double area();}interface Face2{abstract void setColor(String c);}interface Face3 extends Face1,Face2{abstract void volume();}public class Main8_12implements Face3 {private double radius;private int height;protected String color ;public Main8_12(double r,int h){radius = r;height = h;}public double area(){return PI*radius*radius;}public void setColor(String c){color = c;System.out.println("颜色："+color);}public void volume(){System.out.println("圆柱体体积 ="+area()*height);}public static void main(String[] args){Main8_12 volu = new Main8_12(3.0,2);volu.setColor("红色");volu.volume();}}

interface Face1_13{final double PI = 3.14;abstract double area();}interface Face2_13{abstract void volume();}public class Main8_13 implements Face1_13,Face2_13{private double radius;private int height;public Main8_13(double r,int h){radius = r;height = h;}public double area(){return PI*radius*radius;}public void volume(){System.out.println("圆柱体体积 ="+area()*height);}public static void main(String[] args){Main8_13 volu = new Main8_13(5.0,2);volu.volume();}}

public class Main8_14 {private int age;public class Student{String name;public Student(String n,int a){name = n;age = a;}public void output(){System.out.println("姓名："+this.name+";年龄："+age);}}public void output(){Student stu = new Student("刘洋",24);stu.output();}public static void main(String[] args){Main8_14 g = new Main8_14();g.output();}}

public class Main8_15 {public static void main(String[] args){(new Inner(){void setName(String n){name = n;System.out.println("姓名："+name);}}).setName("张    华");}static class Inner{String name;}}