JAVA习题答案.pdf

6.2 修改本章 student 类，每个学生对象包含三次成绩测验，利用参数设置所有实例值，通 过重载构造方法，将每次测验的初始值设置为零，在提供哟个 setTestScore 方法，接收两个 参数，测验编号（1-3)与成绩，同时在提供一个 getTestScore 方法，接受测验编号并返回对 应成绩。提供一个 average 方法，计算并返回该学生的平均成绩。修改 tostring 方法，返回 的字符串因包含该学生的测验成绩与平均成绩。设置 main(): public classAddress private String streeAddress,city,state; private long zipCode; publicAddress(String a,String b,String c,long d) streeAddress=a; city=b; state=c; zipCode=d; public String toString() String str; str=streeAddress+“n“+city+“, “+state+“ “+zipCode; return str; public class Student private String firstName,lastName; private Address homeAddress,schoolAddress; private float score1,score2,score3; public Student (String a,String b,Address c,Address d) firstName=a; lastName=b; homeAddress=c; schoolAddress=d; score1=0; score2=0; score3=0; public void setTestScore(int x,float y) switch(x) case 1:score1=y;break; case 2:score2=y;break; case 3:score3=y;break; public float getTestScore(int x) if(x=1) return score1; else if(x=2) return score2; else return score3; public float average() float ave; ave=(score1+score2+score3)/3; return ave; public String toString() String str; str=firstName+“ “+lastName+“n“; str+=“HomeAddress:n“+homeAddress+“n“+“School Address:n“+schoolAddress+“n“; str+=“TextScore(13): “+score1+“ ; “+score2+“ ; “+score3+“n“+“Average: “+average(); return str; import javax.swing.JOptionPane; public class StudentTest public static void main(String args) String frist=JOptionPane.showInputDialog(null,“Frist name:“); String last=JOptionPane.showInputDialog(null,“Last name:“); JOptionPane.showMessageDialog(null,“Input the home address:“); String a=JOptionPane.showInputDialog(null,“Street address:“); String b=JOptionPane.showInputDialog(null,“City:“); String c=JOptionPane.showInputDialog(null,“State:“); String input1=JOptionPane.showInputDialog(null,“Zip code:“); long d=Integer.parseInt(input1); Address home=new Address(a,b,c,d); JOptionPane.showMessageDialog(null,“Input the school address:“); String e=JOptionPane.showInputDialog(null,“Street address:“); String f=JOptionPane.showInputDialog(null,“City:“); String g=JOptionPane.showInputDialog(null,“State:“); String input2=JOptionPane.showInputDialog(null,“Zip code:“); long h=Integer.parseInt(input2); Address school=newAddress(e,f,g,h); Student student=new Student(frist,last,home,school); int again=0; while(again=0) String input3=JOptionPane.showInputDialog(null,“测验次数:“); int i=Integer.parseInt(input3); if(i3) JOptionPane.showMessageDialog(null,“次数应低于 3!“); continue; String input4=JOptionPane.showInputDialog(null,“the score:“); float j=Float.parseFloat(input4); student.setTestScore(i, j); again=JOptionPane.showConfirmDialog(null,“Again?“); again=JOptionPane.showConfirmDialog(null,“查询测验成绩?“); if(again=0) while(again=0) String input3=JOptionPane.showInputDialog(null,“测验次数:“); int i=Integer.parseInt(input3); if(i3) JOptionPane.showMessageDialog(null,“次数应低于 3!“); continue; String str=“第 “+i+“ 次成绩为: “+student.getTestScore(i); JOptionPane.showMessageDialog(null,str); again=JOptionPane.showConfirmDialog(null,“Again?“); JOptionPane.showMessageDialog(null,student.toString(); 6.3 设计并实现一个表示在校课程的 Course 类，一个课程对象至少掌握五名学生的学习情 况， 可以使用上一个 student 类， Course 类的构造方法只接受课程名臣。 提供一个 addStudent 的方法，接受一个 Student 参数（Course 对相应记录选修此课程全部有效学生） 。提供一个 averrage 方法，计算并返回全部学生的平均分。在提供一个 roll 方法，打印选修这门课程的 所有学生。main 方法，创建一个这样课程，再添加几名学生，最后打印出学生名册和测验 成绩。 import javax.swing.JOptionPane; public class Course private String classname; private Student student=new Student30; int i=0; public Course(String a,Student b) classname=a; studenti=b; i+; public void addStudebt(Student a) studenti=a; i+; public float average() float ave=0,sum=0; for(int j=0;j3) JOptionPane.showMessageDialog(null,“次数应低于 3!“); continue; String input4=JOptionPane.showInputDialog(null,“the score:“); float j=Float.parseFloat(input4); course.setScore(k,i,j); again=JOptionPane.showConfirmDialog(null,“Again?“); String str=“所有学生平均成绩: “+course.average(); JOptionPane.showMessageDialog(null,str); course.roll(); 8.1 设计并实践从 coin 中导出 MonetaryCoin 类。储存硬币面值，同时添加返回面值的方法。 通过创建 main 实例多个对象并计算面值总和。 public class Coin private final int HEADS=0; private final int TAILS=1; private int face; public Coin() flip(); public void flip() face=(int)(Math.random()*2); public boolean isHeads() return(face=HEADS); public String toString() String faceName; if(face=HEADS) faceName=“Hedas“; else faceName=“Tails“; return faceName; class MonetaryCoin extends Coin private int money; public MonetaryCoin(int a) money=a; flip(); public int get() return money; import javax.swing.*; public class Cointest public static void main(String args) String input=JOptionPane.showInputDialog(null,“输入要投的硬币数:“); int n=Integer.parseInt(input); MonetaryCoin coin=new MonetaryCoinn; String str=“投掷结果:n“; for(int i=0;in;i+) input=JOptionPane.showInputDialog(null,“输入第“+(i+1)+“枚硬币的面额:“); int m=Integer.parseInt(input); coini=new MonetaryCoin(m); str+=coini.toString()+“, “; float sum=0; for(int j=0;jn;j+) sum+=coinj.get(); JOptionPane.showMessageDialog(null,str+“n“+“面值总和：“+sum); 8.2 设计代表医院职工的类，有医生，护士，管理人员等。依据不同员工定义相应的方法， 并打印相关信息。 import javax.swing.*; public abstract class Hospital String name,sex; int age; abstract void print(); public String get_name(String a) if(a.equals(name) return name; else return null; public int get_age(int a) if(age=a) return age; else return 0; public String get_sex(String a) if(a.equals(sex) return sex; else return null; public void set_name(String a) name=a; public void set_age(int a) age=a; public void set_sex(String a) sex=a; class Doctor extends Hospital String keshi; public Doctor(String a,int b,String c,String d) name=a; age=b; sex=c; keshi=d; public void print() JOptionPane.showMessageDialog(null, “医生n 姓名: “+name+“n 年龄: “ +age+“n 性 别: “ +sex+“n 科室: “+keshi); public String get_keshi(String a) if(a.equals(keshi) return keshi; else return null; public void set_keshi(String a) keshi=a; class Nurse extends Hospital String bingf; public Nurse(String a,int b,String c,String d) name=a; age=b; sex=c; bingf=d; public void print() JOptionPane.showMessageDialog(null, “护士n 姓名: “+name+“n 年龄: “ +age+“n 性 别: “ +sex+“n 负责病房: “+bingf); public String get_bingf(String a) if(a.equals(bingf) return bingf; else return null; public void set_keshi(String a) bingf=a; classAdministrator extends Hospital String xiangm; publicAdministrator(String a,int b,String c,String d) name=a; age=b; sex=c; xiangm=d; public void print() JOptionPane.showMessageDialog(null, “ 管 理 人 员 n 姓 名 : “+name+“n 年 龄 : “ +age+“n 性别: “ +sex+“n 管理项目: “+xiangm); public String get_keshi(String a) if(a.equals(xiangm) return xiangm; else return null; public void set_keshi(String a) xiangm=a; import javax.swing.JOptionPane; public class Hospitaltest public static void main(String args) Hospital worker; String input=JOptionPane.showInputDialog(null,“输入职工岗位： n(doctor1; nurse2; administrator3)“); int a=Integer.parseInt(input); String name=JOptionPane.showInputDialog(null,“输入姓称：“); input=JOptionPane.showInputDialog(null,“输入年龄:“); int age=Integer.parseInt(input); String sex=JOptionPane.showInputDialog(null,“输入性别：“); if(a=1) String keshi=JOptionPane.showInputDialog(null,“输入工作科室：“); worker=new Doctor(name,age,sex,keshi); worker.print(); else if(a=2) String bingf=JOptionPane.showInputDialog(null,“输入负责病房:“); worker=new Nurse(name,age,sex,bingf); worker.print(); else if(a=3) String xiangm=JOptionPane.showInputDialog(null,“输入管理项目：“); worker=newAdministrator(name,age,sex,xiangm); worker.print(); else JOptionPane.showMessageDialog(null,“ERROR!“); 8.3 设计代表书的类，有小说，杂志，教科书等。类中有不同的数据，并打印相关信息。 import javax.swing.*; public abstract class Books String name; int pages; abstract void print(); int get_name(String a) if(name.equals(a) return 1; else return 0; int get_pages(int a) if(pages=a) return 1; else return 0; void set_name(String a) name=a; void set_pages(int a) pages=a; class Novels extends Books String author; String primary; public Novels(String a,int b,String c,String d) name=a; pages=b; author=c; primary=d; void print() JOptionPane.showMessageDialog(null,“书名: “+name+“n 页数: “+pages+“n 作者: “+author+“n 主人公: “+primary,“书的信息“,JOptionPane.INFORMATION_MESSAGE); int get_auther(String a) if(author.equals(a) return 1; else return 0; int get_primary(String a) if(primary.equals(a) return 1; else return 0; void set_auther(String a) author=a; void set_primary(String a) primary=a; class Magazines extends Books int num; public Magazines(String a,int b,int c) name=a; pages=b; num=c; void print() JOptionPane.showMessageDialog(null,“书名: “+name+“n 页数: “+pages+“n 期号: “+num,“书的信息“,JOptionPane.INFORMATION_MESSAGE); int get_num(int a) if(num=a) return 1; else return 0; void set_num(int a) num=a; class Textbooks extends Books String classes; public Textbooks(String a,int b,String c) name=a; pages=b; classes=c; void print() JOptionPane.showMessageDialog(null,“书名: “+name+“n 页数: “+pages+“n 科目: “+classes,“书的信息“,JOptionPane.INFORMA