/*** @version 1.10 1999-11-13* @author Cay Horstmann*/public class Employee
{private String name;private double salary;public native void raiseSalary(double byPercent);public Employee(String n, double s){name = n;salary = s;}public void print(){System.out.println(name + " " + salary);}static{System.loadLibrary("Employee");}
}

import java.util.*;public class StudentTest{
public static void main(String[] args){Student[] staff = new Student[4];System.out.println("请输入学生姓名、性别、Java成绩");Scanner in = new Scanner(System.in); for(int i=0;i<staff.length;i++) {staff[i]=new Student(in.next(),in.next(),in.nextInt());}System.out.println("name"+"sex"+"javascore");for (Student e: staff)System.out.println(e.getName()+e.getSex()+e.getjavaScore());}}class Student{private String name;private String sex;private int javascore;public Student(String n, String s, int j){name = n;sex = s;javascore =j;}public String getName(){return name;}public String getSex(){return sex;}public int getjavaScore(){return javascore;}}

/**/*** This program demonstrates static methods.* @version 1.01 2004-02-19* @author Cay Horstmann*/public class StaticTest{public static void main(String[] args){//用三个Employee对象填充staff数组Employee[] staff = new Employee[3];staff[0] = new Employee("Tom", 40000);staff[1] = new Employee("Dick", 60000);staff[2] = new Employee("Harry", 65000);//打印出员工反对的信息for (Employee e : staff){e.setId();System.out.println("name=" + e.getName() + ",id=" + e.getId() + ",salary="+ e.getSalary());}int n = Employee.getNextId(); // calls static methodSystem.out.println("Next available id=" + n);}}class Employee{private static int nextId = 1;private String name;private double salary;private int id;public Employee(String n, double s){name = n;salary = s;id = 0;}public String getName(){return name;}public double getSalary(){return salary;}public int getId(){return id;}public void setId(){id = nextId; //将此ID设置为下一个可用IDnextId++;}public static int getNextId(){return nextId; //返回static域
           }public static void main(String[] args) // unit test
           {Employee e = new Employee("Harry", 50000);System.out.println(e.getName() + " " + e.getSalary());}}

    /*** This program demonstrates parameter passing in Java.* @version 1.00 2000-01-27* @author Cay Horstmann*/public class ParamTest{public static void main(String[] args){//该方法不能修改数值参数System.out.println("Testing tripleValue:");double percent = 10;System.out.println("Before: percent=" + percent);tripleValue(percent);System.out.println("After: percent=" + percent);//该方法可以改变对象参数的状态System.out.println("\nTesting tripleSalary:");Employee harry = new Employee("Harry", 50000);System.out.println("Before: salary=" + harry.getSalary());tripleSalary(harry);System.out.println("After: salary=" + harry.getSalary());          //该方法可以将新对象附加到对象参数        System.out.println("\nTesting swap:");Employee a = new Employee("Alice", 70000);Employee b = new Employee("Bob", 60000);System.out.println("Before: a=" + a.getName());System.out.println("Before: b=" + b.getName());swap(a, b);System.out.println("After: a=" + a.getName());System.out.println("After: b=" + b.getName());}public static void tripleValue(double x) // doesn't work
       {x = 3 * x;System.out.println("End of method: x=" + x);}public static void tripleSalary(Employee x) // works
       {x.raiseSalary(200);System.out.println("End of method: salary=" + x.getSalary());}public static void swap(Employee x, Employee y){Employee temp = x;x = y;y = temp;System.out.println("End of method: x=" + x.getName());System.out.println("End of method: y=" + y.getName());}}class Employee {private String name;private double salary;public Employee(String n, double s){name = n;salary = s;}public String getName(){return name;}public double getSalary(){return salary;}public void raiseSalary(double byPercent){double raise = salary * byPercent / 100;salary += raise;}}

import java.util.*;/*** This program demonstrates object construction.* @version 1.01 2004-02-19* @author Cay Horstmann*/
public class ConstructorTest
{public static void main(String[] args){//用单个Employee对象填充staff数组Employee[] staff = new Employee[3];staff[0] = new Employee("Harry", 40000);staff[1] = new Employee(60000);staff[2] = new Employee();//打印出员工反对信息for (Employee e : staff)System.out.println("name=" + e.getName() + ",id=" + e.getId() + ",salary="+ e.getSalary());}
}class Employee
{private static int nextId;private int id;private String name = ""; //实例字段初始化private double salary;// static initialization blockstatic{Random generator = new Random();//从0-9999随机分配下一ID的地址nextId = generator.nextInt(10000);}
   {id = nextId;nextId++;}public Employee(String n, double s){name = n;salary = s;}public Employee(double s){//调用雇员构造函数this("Employee #" + nextId, s);}//默认构造函数public Employee(){// salary not explicitly set--initialized to 0// id initialized in initialization block
   }public String getName(){return name;}public double getSalary(){return salary;}public int getId(){return id;}
}

import com.horstmann.corejava.*;

import static java.lang.System.*;/*** This program demonstrates the use of packages.* @version 1.11 2004-02-19* @author Cay Horstmann*/
public class PackageTest
{public static void main(String[] args){// because of the import statement, we don't have to use // com.horstmann.corejava.Employee hereEmployee harry = new Employee("Harry Hacker", 50000, 1989, 10, 1);harry.raiseSalary(5);// because of the static import statement, we don't have to use System.out hereout.println("name=" + harry.getName() + ",salary=" + harry.getSalary());}
}

 package com.horstmann.corejava;//这个文件中的类是这个包的一部分
  import java.time.*;//导入语句位于PACKAGE语句之后/*** @version 1.11 2015-05-08* @author Cay Horstmann*/public class Employee{private String name;private double salary;private LocalDate hireDay;public Employee(String name, double salary, int year, int month, int day){this.name = name;this.salary = salary;hireDay = LocalDate.of(year, month, day);}public String getName(){return name;}public double getSalary(){return salary;}public LocalDate getHireDay(){return hireDay;}public void raiseSalary(double byPercent){double raise = salary * byPercent / 100;salary += raise;}}

import java.util.*;

public class Rectangle {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
System.out.println("输入长方形的长:");
Float length = in.nextFloat();
System.out.println("输入长方形的宽:");
Float width = in.nextFloat();
System.out.println("输入圆的半径:");
Float radius = in.nextFloat();
Rec l = new Rec(width, length);
Cir r = new Cir(radius);
System.out.println("矩形周长=" + l.getPerimeter() + "矩形面积=" + l.getArea());
System.out.println("圆周长=" + r.getPerimeter() + "圆面积=" + r.getArea());
float c = l.getPerimeter() + r.getPerimeter();
double s = l.getArea() + r.getArea();
System.out.println("矩形和圆的周长之和：" + c + "矩形和圆的面积之和：" + s);
}

}

class Rec {
private Float width;
private double length;

public Rec(Float w, Float l) {
width = w;
length = l;
}

public Float getPerimeter() {
Float Perimeter = (float) ((width + length) * 2);
return Perimeter;
}

public Float getArea() {
Float Area = (float) (width * length);
return Area;
}
}

class Cir {

private double radius;
double PI = 3.14;

public Cir(Float r) {
radius = r;
}

public Float getPerimeter() {
Float Perimeter = (float) (2 * PI * radius);
return Perimeter;
}

public Float getArea() {
Float Area = (float) (PI * radius * radius);
return Area;
}

}