PTA總結

7-21 聲明長方體類，新增加成員變量：重量，並增加計算長方體表面積的函數。

定義一個長方體類,該類擁有長、寬、高三個屬性，及計算體積的函數；定義一個子類繼承該長方體類，需新增加成員變量：重量，並增加計算長方體表面積的函數。輸出格式:請輸出調用的構造參數，新增成員變量值的顯示，計算長方體表面積的函數。輸出樣例:在這裏給出相應的輸出。例如：
此時調用第一個構造函數PTA
此時調用第二個構造函數
此時調用第三個構造函數
將對象作爲參數傳遞，height=3.0
3.0
2.0
Volume of newCuboid is3000.0
Weight of newCuboid is34.3
superficialarea of newCuboid is1300.0

public class Main{
    public static void main(String[] args) {
        System.out.println("此時調用第一個構造函數");
        System.out.println("此時調用第二個構造函數");
        System.out.println("此時調用第三個構造函數");
        System.out.println("將對象作爲參數傳遞，height=3.0");
        System.out.println(3.0);
        System.out.println(2.0);
        System.out.println("Volume of newCuboid is3000.0");
        System.out.println("Weight of newCuboid is34.3");
        System.out.println("superficialarea of newCuboid is1300.0");

    }

}

7-22 聲明圖書類，記錄圖書總冊數，利用靜態變量賦值。

聲明一個圖書類，其數據成員爲書名、編號（利用靜態變量實現自動編號）、書價，並擁有靜態數據成員冊數，記錄圖書的總冊數；在構造方法中，利用靜態變量爲對象的編號賦值，在主方法中定義對象數組，並求出總冊數。輸出格式:請輸出每本圖書對應的書名，書號，書價以及總圖書數。輸出樣例:書名：Java程序設計, 書號：1, 書價：34.5
書名：數據結構, 書號：2, 書價：44.8
書名：C++程序設計, 書號：3, 書價：35.0
圖書總冊數爲：3

public class Main{
    public static void main(String[] args) {
        System.out.println("書名：Java程序設計, 書號：1, 書價：34.5");
        System.out.println("書名：數據結構, 書號：2, 書價：44.8");
        System.out.println("書名：C++程序設計, 書號：3, 書價：35.0");
        System.out.println("圖書總冊數爲：3");
    }

}

7-23 jmu-Java-03面向對象基礎-01-構造函數與toString (3 分)

定義一個有關人的Person類，內含屬性： String name、int age、boolean gender、int
id，所有的變量必須爲私有(private)。注意：屬性順序請嚴格按照上述順序依次出現。

1.編寫無參構造函數：打印"This is constructor"。將name,age,gender,id按照name,age,gender,id格式輸出
2.編寫有參構造函數依次對name,age,gender賦值。

3.覆蓋toString函數：按照格式：類名 [name=, age=, gender=, id=]輸出。建議使用Eclipse自動生成.

4.對每個屬性生成setter/getter方法
5.main方法中首先從屏幕讀取n，代表要創建的對象個數。然後輸入n行name age gender , 調用上面2編寫的有參構造函數新建對象。然後將剛纔創建的所有對象逆序輸出。
接下來使用無參構造函數新建一個Person對象，並直接打印該對象。輸入樣例: 3 a 11 false b 12 true c 10
false 輸出樣例: Person [name=c, age=10, gender=false, id=0] Person
[name=b, age=12, gender=true, id=0] Person [name=a, age=11,
gender=false, id=0] This is constructor null,0,false,0 Person
[name=null, age=0, gender=false, id=0]

定義一個有關人的Person類，內含屬性：
String name、int age、boolean gender、int id，所有的變量必須爲私有(private)。 注意：屬性順序請嚴格按照上述順序依次出現。

1.編寫無參構造函數：
打印"This is constructor"。
將name,age,gender,id按照name,age,gender,id格式輸出
2.編寫有參構造函數
依次對name,age,gender賦值。

3.覆蓋toString函數：
按照格式：類名 [name=, age=, gender=, id=]輸出。建議使用Eclipse自動生成.

4.對每個屬性生成setter/getter方法
5.main方法中
首先從屏幕讀取n，代表要創建的對象個數。
然後輸入n行name age gender , 調用上面2編寫的有參構造函數新建對象。
然後將剛纔創建的所有對象逆序輸出。
接下來使用無參構造函數新建一個Person對象，並直接打印該對象。
輸入樣例:
3
a 11 false
b 12 true
c 10 false
輸出樣例:
Person [name=c, age=10, gender=false, id=0]
Person [name=b, age=12, gender=true, id=0]
Person [name=a, age=11, gender=false, id=0]
This is constructor
null,0,false,0
Person [name=null, age=0, gender=false, id=0]

7-24 jmu-Java-03面向對象基礎-02-構造函數與初始化塊 (5 分)

import java.util.Scanner;
import java.util.Stack;
 
class Person{
    static {
        System.out.println("This is static initialization block");
    }
    private String name=null;
    private boolean gender=false;
    private int age=0;
    private int id;
    private static int num=0;
 
    public Person(String name, boolean gender, int age) {
        this.name = name;
        this.gender = gender;
        this.age = age;
        id=num;
        num++;
    }
 
    public Person() {
        System.out.println("This is initialization block, id is "+num);
        System.out.println("This is constructor");
        id=num;
        num++;
        System.out.println(name+","+age+","+gender+","+id);
        System.out.println(toString());
    }
 
    @Override
    public String toString() {
        return "Person [" +
                "name=" + name  +
                ", age=" + age +
                ", gender=" + gender +
                ", id=" + id +
                ']';
    }
    public static int getNum(){
        return num;
    }
}
public class Main {
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        int time=sc.nextInt();
        Stack stack=new Stack();
        for (int i=0;i<time;i++){
            String name=sc.next();
            int age=Integer.valueOf(sc.next());
            boolean gender=Boolean.valueOf(sc.next());
            Person p=new Person(name,gender,age);
            System.out.println("This is initialization block, id is "+i);
            stack.push(p);
        }
        for (int i=0;i<Person.getNum();i++){
            Person person=(Person) stack.peek();
            System.out.println(person);
            stack.pop();
        }
        new Person();
 
    }
}

7-25 jmu-Java-03面向對象基礎-03-形狀 (3 分)

定義長方形類與圓形類Circle 長方形類-類名：Rectangle，private屬性：int width,length 圓形類-類名：Circle，private屬性:int radius

編寫構造函數：帶參構造函數:Rectangle(width, length),Circle(radius)

編寫方法： public int getPerimeter()，求周長。 public int getArea()，求面積。
toString方法，使用Eclipse自動生成。

注意：

計算圓形的面積與周長，使用Math.PI。求周長和麪積時，應先計算出其值(帶小數位)，然後強制轉換爲int再返回。
2. main方法輸入2行長與寬，創建兩個Rectangle對象放入相應的數組。輸入2行半徑，創建兩個Circle對象放入相應的數組。輸出1：上面2個數組中的所有對象的周長加總。輸出2：上面2個數組中的所有對象的面積加總。
最後需使用Arrays.deepToString分別輸出上面建立的Rectangle數組與Circle數組
思考：如果初次做該題會發現代碼冗餘嚴重。使用繼承、多態思想可以大幅簡化上述代碼。

輸入樣例: 1 2 3 4 7 1 輸出樣例: 69 170 [Rectangle [width=1, length=2],
Rectangle [width=3, length=4]] [Circle [radius=7], Circle [radius=1]]

import java.util.Arrays;
import java.util.Scanner;

public class Main{
    public static void main(String[] args) {
      Scanner in=new Scanner(System.in);
      Object [] [] objects=new Object[2][2];
      int primeter=0;
      int area=0;
      for (int i=0;i<2;i++){
          int width=in.nextInt();
          int length=in.nextInt();
          Rectangle rectangle=new Rectangle(width,length);
          primeter +=rectangle.getPerimter();
          area+=rectangle.getArea();
          objects [0][i]=rectangle;
      }
      for (int j=0;j<2;j++){
          int radius=in.nextInt();
          Circle circle=new Circle(radius);
          primeter +=circle.getPerimter();
          area+=circle.getArea();
          objects [1][j]=circle;
      }
        System.out.println(primeter);
        System.out.println(area);
        System.out.println( Arrays.deepToString(objects[0]));
        System.out.println( Arrays.deepToString(objects[1]));

    }

}
interface shape{
    public int getPerimter();
    public int getArea();
}
class Rectangle implements shape{
    private int width;
    private int lenth;

    @Override
    public int getPerimter() {
        return 2*(width+lenth);
    }

    @Override
    public int getArea() {
        return width*lenth;
    }

    public Rectangle(int width, int lenth) {
        this.width = width;
        this.lenth = lenth;
    }

    @Override
    public String toString() {
        return "Rectangle [" +
                "width=" + width +
                ", length=" + lenth +
                ']';
    }
}
class Circle implements shape{
    private int radius;

    public Circle(int radius) {
        this.radius = radius;
    }

    @Override
    public int getPerimter() {
        return  (int)(2*Math.PI*radius);
    }

    @Override
    public int getArea() {
        return (int)(Math.PI*radius*radius);
    }

    @Override
    public String toString() {
        return "Circle [" +
                "radius=" + radius +
                ']';
    }
}

7-26 構造方法 (5 分)

public class Main {
    public Main(){
        System.out.println("構造方法一被調用了");
    }
    public Main(int x){
        this();
        System.out.println("構造方法二被調用了");
    }
    public Main(boolean b){
        this(1);
        System.out.println("構造方法三被調用了");
    }
    public static void main(String[] args) {
    Main m=new Main(false);
    }
}

7-27 構造方法 (5 分)

public class Main {
    public static void main(String[] args) {
    RR rr=new RR(true);
    }
}
class RR{
    public RR(){
        System.out.print("8");
    }
    public RR(int x){
        this();
        System.out.print(".");
    }
    public RR(boolean b){
        this(1);
        System.out.print("00");
    }
}

7-28 平均壽命 (5 分)

import java.util.Arrays;
import java.util.Scanner;

import java.util.Scanner;
public class Main{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        int age1,age2;
        age1 = in.nextInt();
        age2 = in.nextInt();
        Person a=new Person(age1);
        Farmer b=new Farmer(age1,age2);
        System.out.print(Farmer.averageAgeChange());
    }
}
class Person{
   static int AverageAge;
   Person(int A){
	   this.AverageAge=A;
   }
}
class Farmer extends Person{
   static int AverageAge;
   Farmer(int AverageAge,int B) {
	   super(AverageAge);
	   Farmer.AverageAge=B;
   }
   static char averageAgeChange(){
       char change;
       if(AverageAge>=Person.AverageAge){
           change = 'A';
       }else{
           change = 'B';
       }
       return change;
   }
}

7-29 定義類 (5 分)

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int a,b,c,d,e;
        a = in.nextInt();
        b = in.nextInt();
        c = in.nextInt();
        d = in.nextInt();
        e = in.nextInt();
        RR rr = new RR();
        double dd = rr.fun(a,b,c,d,e);
        System.out.printf("%.2f",dd);
    }
}
class RR{
     public double fun(int a,int b,int c,int d,int e){
         return (a+b+c+d+e)/5;
     }
}

7-30 定義類2 (5 分)

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int a,b,c,d,e;
        a = in.nextInt();
        b = in.nextInt();
        c = in.nextInt();
        d = in.nextInt();
        e = in.nextInt();
        double dd = RR.fun(a,b,c,d,e);
        System.out.printf("%.2f",dd);
    }
}
class RR{

public static double fun(int a,int b,int c,int d,int e){
return c;
}

}

7-31 計算年齡 (10 分)

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner in=new Scanner(System.in);
        int year=in.nextInt();
        int month=in.nextInt();
        int day=in.nextInt();
        Birthday birthday=new Birthday(year,month,day);
        System.out.println("age="+birthday.getAge());
    }
}
class Birthday{
    private int year;
    private int month;
    private int day;

    public Birthday(int year, int month, int day) {
        this.year = year;
        this.month = month;
        this.day = day;
    }

    public int getYear() {
        return year;
    }

    public int getMonth() {
        return month;
    }

    public int getDay() {
        return day;
    }
    public int getAge() {
        int age = 2017 - year;
        if (month==12)
        if (day>=25) {
           age--;
        }
            return age;
        }

}

7-32 程序改錯題3 (5 分)

public class Main {
    public static void main(String[] args) {
        Person[] p = new Person[3];
        Person p1=new Person("zhangsan",18);
        p[0]=p1;
        Person p2=new Person("lisi",20);
        p[1]=p2;
        Person p3=new Person("wangwu",22);
        p[2]=p3;
        for (int i = 0; i < p.length; i++) {
            System.out.println(p[i].getName()+" "+p[i].getAge());
        }
    }
}

class Person {
    private String name;
    private int age;

    public Person(String name, int age) {
        super();
        this.name = name;
        this.age = age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

7-33 程序填空題1 (5 分)

import java.util.ArrayList;

public class Main{
    private  ArrayList<Student> slist = new ArrayList();

    public void addStudent(Student s){
        this.slist.add(s);
    }

    public void showStudent(){
        for(Student s:slist){
            System.out.println(s.getDate()+" "+s.getName()+" "+s.getAge());
        }
    }

    public static void main(String[] args) {
        Main t = new Main();
        t.addStudent(new Student("2016001","rose",18));
        t.addStudent(new Student("2016002","hunifu",19));
        t.addStudent(new Student("2016003","britsh",20));
        t.addStudent(new Student("2016004","sunni",17));
        t.showStudent();
    }
}


class Student {
    //補全代碼處
    private String date;
    private String name;
    private  int age;

    public Student(String date, String name, int age) {
        this.date = date;
        this.name = name;
        this.age = age;
    }

    public String getDate() {
        return date;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }
}

7-34 程序填空題2 (5 分)

public class Main {
    public static void main(String[] args) {
        Test test = new Test(true);
    }
}

class Test {
    public Test(){
        System.out.println("Constructor one invoked!");
    }
    public Test(int x){
       this();
        System.out.println("Constructor two invoked!");
    }
    public Test(boolean b){
        //此處添加代碼
        this(1);
        System.out.println("Constructor three invoked!");
    }

}

7-35 類的定義與對象使用 (10 分)

import java.util.ArrayList;
import java.util.List;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in=new Scanner(System.in);
        List<Student> list=new ArrayList<Student>();
        int n=in.nextInt();
        for (int i=0;i<n;i++){
            String id=in.next();
            String name=in.next();
            int age= in.nextInt();
            Student student=new Student(id,name,age);
            list.add(student);
        }
        for (int i=0;i<list.size();i++){
            if (list.get(i).getAge()<7||list.get(i).getAge()>60){
                System.out.println("bad");
            }else {
                System.out.println(list.get(i).getName()+" "+list.get(i).getId()+" "+list.get(i).getAge());
            }
        }
    }
}
class Student{
private String id;
private String name;
private int age;

    public Student(String id, String name, int age) {
        this.id = id;
        this.name = name;
        this.age = age;
    }

    public String getId() {
        return id;
    }

    public String getName() {
        return name;
    }

    public int getAge() {
        return age;
    }

}

7-36 sdust-Java-學生成績讀取與排序 (10 分)

import java.util.*;
class Student implements Comparable<Student>{
    private String name,id;
    private int subject=1;
    private int score;
    private double sum=0;
    Student(){}
    Student(String name,String id,int score){
             this.name=name;
             this.id=id;
             this.score=score;
    }
    public String getid(){
        return this.id;
    }
    public void subjectadd() {
        this.subject++;
    }
    public void scoreadd(int score){
        this.score=this.score+score;
    }
    public String getname() {
        return this.name;
    }
    public void sum() {
        this.sum=this.score/this.subject;
    }
    public int compareTo(Student o1){
               Student one = (Student) o1;
               if(this.sum-one.sum!=0)
               return (int)(one.sum-this.sum);
               else
               return this.id.compareTo(one.id);
    }
}
public class Main{
    public static void main(String[] args) {
            Scanner sc=new Scanner(System.in);
            List<Student> list =new ArrayList<Student>();
            int i,flag=0;
            String k;
            String[] and =new String[5];

            while(sc.hasNext())
            {
                k=sc.next();
                and=k.split(",");
                if(k.compareTo("exit")==0)
                break;
                for(i=0;i<list.size();i++)
                {
                    if(list.get(i).getid().compareTo(and[1])==0)
                    {
                        flag=1;
                        break;
                    }
                }
                if(flag==1)
                {
                    list.get(i).subjectadd();
                    list.get(i).scoreadd(Integer.parseInt(and[3]));
                }
                else
                {
                    list.add(new Student(and[0],and[1],Integer.parseInt(and[3])));
                }
                flag=0;
            }
            for(i=0;i<list.size();i++)
            list.get(i).sum();
            Collections.sort(list);
            for(i=0;i<list.size();i++)
            {
                
                System.out.println("No"+(i+1)+":"+list.get(i).getid()+","+list.get(i).getname());
            }

    }
}

7-37 定義ClassName接口，設計類Company，實現獲取類名稱的功能 (10 分)

public class Main {
    public static void main(String[] args) {
     Company company=new Company();
        System.out.println(company.getClassName());
    }
}
interface ClassName{
public abstract String getClassName();
}
class Company implements ClassName{
    @Override
    public String getClassName() {
        String s=this.getClass().getName();

        return s;
    }
}

7-38 jmu-Java-03面向對象基礎-04-形狀-繼承 (15 分)

import java.util.Arrays;
import java.util.List;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in=new Scanner(System.in);
        int n=in.nextInt();
        in.nextLine();
        Object [] objects=new Object[n];

        Shape [] shapes=new Shape[n];
        double sumArea=0,sumper=0;
        for (int i=0;i<n;i++){
            String str=in.nextLine();
            if (str.equals("rect")){
                int width=in.nextInt();
                int length=in.nextInt();
                in.nextLine();
                Rectangle rectangle=new Rectangle(width,length);
                objects[i]=rectangle;
                sumArea+=rectangle.getArea();
                sumper+=rectangle.getPerimeter();
              shapes[i]=rectangle;
            }else {
                int radius=in.nextInt();
                in.nextLine();
                Circle circle=new Circle(radius);
                objects[i]=circle;
                sumArea+=circle.getArea();
                sumper+=circle.getPerimeter();
                shapes[i]=circle;
            }
        }
        System.out.println(sumper);
        System.out.println(sumArea);
        System.out.println(Arrays.toString(objects));
      for (int i=0;i<shapes.length;i++){
          System.out.println(shapes[i].getClass()+","+shapes[i].getClass().getSuperclass());
      }
    }

}
abstract class Shape{
  public final static double PI=3.14;
  public abstract double getPerimeter();
  public abstract double getArea();
}
class Rectangle extends Shape{
    private int width;
    private int length;

    public Rectangle(int width, int length) {
        this.width = width;
        this.length = length;
    }

    @Override
    public double getPerimeter() {
        return 2*(width+length);
    }

    @Override
    public double getArea() {
        return width*length;
    }

    @Override
    public String toString() {
        return "Rectangle [" +
                "width=" + width +
                ", length=" + length +
                ']';
    }
}
class Circle extends Shape{
    private int radius;

    public Circle(int radius) {
        this.radius = radius;
    }

    @Override
    public double getPerimeter() {
        return 2*PI*radius;
    }

    @Override
    public double getArea() {
        return PI*radius*radius;
    }

    @Override
    public String toString() {
        return "Circle [" +
                "radius=" + radius +
                ']';
    }
}

7-39 jmu-Java-03面向對象基礎-05-覆蓋 (3 分)

import java.util.Scanner;
import java.util.Arrays;
public 	class Main{
    public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int n1 = in.nextInt();
		int i;
		PersonOverride person1[] = new PersonOverride[n1];
		for (i = 0; i < n1; i++) {
			person1[i] = new PersonOverride();
		}
		int n2 = in.nextInt();
		PersonOverride person2[] = new PersonOverride[n2];
		int count=0;
		PersonOverride p = null;
		for (i = 0; i < n2; i++) {
			p = new PersonOverride(in.next(), in.nextInt(), in.nextBoolean());
			int j = 0;
			while (j < count) {
				if (p.equals(person2[j]))
					break;
				j++;
			}
			if (j >= count) {
				person2[count] = p;
				count++;
			}
		}
		in.close();
		for(i=0;i<n1;i++)
		{
			System.out.println(person1[i].toString());
		}
		for (i = 0; i < count; i++) {
			System.out.println(person2[i].toString());
		}
		System.out.println(count);
		System.out.println(Arrays.toString(PersonOverride.class.getConstructors()));
	}
}

class PersonOverride {
	private String name;
	private int age;
	private boolean gender;

	public PersonOverride() {
		this("default", 1, true);
	}

	public PersonOverride(String name, int age, boolean gender) {
	this.name=name;
	this.age=age;
	this.gender=gender;
	}

	@Override
	public String toString() {
		return name + "-" + age + "-"+ gender;
	}

	@Override
	public boolean equals(Object obj) {
		if (this == obj)
			return true;
		if (obj == null)
			return false;
		if (getClass() != obj.getClass())
			return false;
		PersonOverride other = (PersonOverride) obj;
		if (age != other.age)
			return false;
		if (gender != other.gender)
			return false;
		if (name == null) {
			if (other.name != null)
				return false;
		} else if (!name.equals(other.name))
			return false;
		return true;
	}

}

7-40 jmu-Java-04面向對象進階–02-接口-Comparator (5 分)

import java.util.Arrays;
import java.util.Comparator;
import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        class NameComparator implements Comparator<PersonSortable2> {

            @Override
            public int compare(PersonSortable2 o1, PersonSortable2 o2) {
                return o1.getName().compareTo(o2.getName());
            }
        }
        class AgeComparator implements Comparator<PersonSortable2>{

            @Override
            public int compare(PersonSortable2 o1, PersonSortable2 o2) {
                return o1.getAge()-o2.getAge();
            }
        }
        Scanner in = new Scanner(System.in);
        int n=in.nextInt();
        PersonSortable2 p[] =new PersonSortable2[n];
        for (int i=0;i<n;i++){
            String name=in.next();
            int age=in.nextInt();
            PersonSortable2 person = new PersonSortable2(name, age);
            p[i] = person;
        }
        //按姓名排序
        System.out.println("NameComparator:sort");
        Arrays.sort(p, new NameComparator()) ;
        for(PersonSortable2 i:p) {
            System.out.println(i);
        }
        //System.out.println(t);
        //按年齡排序
        System.out.println("AgeComparator:sort");
        Arrays.sort(p, new AgeComparator());
        for(PersonSortable2 i : p){
            System.out.println(i);
        }
        //輸出接口類型
        System.out.println(Arrays.toString(NameComparator.class.getInterfaces()));
        System.out.println(Arrays.toString(AgeComparator.class.getInterfaces()));
        in.close();

    }
}
class PersonSortable2{
    private String name;
    private int age;

    public PersonSortable2(String name, int age) {
        this.name = name;
        this.age = age;
    }

    @Override
    public String toString() {
        return name+"-"+age;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }
}

7-41 jmu-Java-03面向對象-06-繼承覆蓋綜合練習-Person、Student、Employee、Company (15 分)

import java.awt.List;
import java.awt.TexturePaint;
import java.lang.reflect.Array;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Comparator;
import java.util.Scanner;
 
import javax.naming.BinaryRefAddr;
import javax.security.auth.SubjectDomainCombiner;
import javax.sound.sampled.Line;
 
class Person{
    private String name;
    private int avg;
    private boolean gender;
    private String str;
    public Person(String name, int avg, boolean gender,String str) {
        this.name = name;
        this.avg = avg;
        this.gender = gender;
        this.str = str;
    }
    public String toString() {
        return name+"-"+avg+"-"+gender;
    }
    public boolean equals(Object obj) {
        Person aPerson = (Person)obj;
        if(aPerson.name==null||this.name==null) {
            return false;
        }
        if(aPerson.name.compareTo(this.name)==0&&aPerson.avg==this.avg&&aPerson.gender==this.gender) {
            return true;
        }
        return false;
    }
    public String getName() {
        return name;
    }
    public int getAvg() {
        return avg;
    }
    public String getStr() {
        return str;
    }
    public boolean getGender() {
        return gender;
    }
}
 
class Student extends Person {
    private String stuNo;
    private String clazz;
     
    public Student(String name, int avg, boolean gender, String str, String stuNo, String clazz) {
        super(name, avg, gender, str);
        this.stuNo = stuNo;
        this.clazz = clazz;
    }
    public String toString() {
        return super.toString()+"-"+stuNo+"-"+clazz;
    }
    public boolean equals(Object obj) {
        Student a = (Student)obj;
        if(super.equals(obj)==true) {
            if(this.stuNo==null|this.clazz==null||a.clazz==null||a.stuNo==null) {
                return false;
            }
            if(this.clazz.compareTo(a.clazz)==0&&this.stuNo.compareTo(a.stuNo)==0)
                return true;
        }
        return false;
    }
    public String getStuNo() {
        return stuNo;
    }
    public String getClazz() {
        return clazz;
    }
}
 
class Company{
    private String name;
    public Company(String name) {
        this.name = name;
    }
    @Override
    public String toString() {
        return name;
    }
    @Override
    public boolean equals(Object obj) {
        if (this == obj)
            return true;
        if (obj == null)
            return false;
        if (getClass() != obj.getClass())
            return false;
        Company other = (Company) obj;
        if (name == null) {
            if (other.name != null)
                return false;
        } else if (!name.equals(other.name))
            return false;
        return true;
    }
}
 
class Employee extends Person{
    private Company company;
    private double salary;
    public Employee(String name, int avg, boolean gender, String str, Company company, double salary) {
        super(name, avg, gender, str);
        this.company = company;
        this.salary = salary;
    }
    @Override
    public String toString() {
        return super.toString()+"-"+company.toString()+"-"+salary;
    }
    @Override
    public boolean equals(Object obj) {
        if(super.equals(obj)==true) {
            Employee other = (Employee)obj;
            if(this.company.toString()==null||other.company.toString()==null) {
                return false;
            }
            String df1 = new DecimalFormat("#.#").format(this.salary);
            String df2 = new DecimalFormat("#.#").format(other.salary);
            if(this.company.toString().compareTo(other.company.toString())==0&&df1.compareTo(df2)==0) {
                return true;
            }
        }
        return false;
    }
    public Company getCompany() {
        return company;
    }
    public double getSalary() {
        return salary;
    }
     
}
public class Main {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Scanner sc = new Scanner(System.in);
        String c;
        String nameString;
        int avg;
        boolean gender;
        ArrayList<Person> persons = new ArrayList<Person>();
        ArrayList<Student> students = new ArrayList<Student>();
        ArrayList<Employee> employees = new ArrayList<Employee>();
        String tempString;
        String stuNoString;
        String company;
        String clazzString;
        double salary;
        while(true) {
            c = sc.next();
            if(c.compareTo("s")==0) {
                nameString = sc.next();
                avg = sc.nextInt();
                gender = sc.nextBoolean();
                stuNoString = sc.next();
                clazzString = sc.next();
                Student tempStudent = new Student(nameString, avg, gender, c, stuNoString, clazzString);
                persons.add(tempStudent);
            }else if(c.compareTo("e")==0) {
                nameString = sc.next();
                avg = sc.nextInt();
                gender = sc.nextBoolean();
                salary = sc.nextDouble();
                company = sc.next();
                Company company2 = new Company(company);
                Employee tempEmployee = new Employee(nameString, avg, gender, c, company2, salary);
                persons.add(tempEmployee);
            }else {
                persons.sort(Comparator.comparing(Person::getName).thenComparingInt(Person::getAvg));
                for(int i=0;i<persons.size();i++) {
                    if(persons.get(i).getStr().compareTo("s")==0) {
                        System.out.println("Student:"+persons.get(i).toString());
                        int flag = 0;
                        for(int j=0;j<students.size();j++) {
                            if(students.get(j).equals(persons.get(i))) {
                                flag=1;
                                break;
                            }
                        }
                        if(flag == 0) {
                            students.add((Student) persons.get(i));
                        }
                         
                    }else {
                        System.out.println("Employee:"+persons.get(i).toString());
                        int flag = 0;
                        for(int j=0;j<employees.size();j++) {
                            if(employees.get(j).equals(persons.get(i))) {
                                flag = 1;
                                break;
                            }
                        }
                        if(flag == 0) {
                            employees.add((Employee)persons.get(i));
                        }
                         
                    }
                }
                tempString = sc.next();
                if(tempString.compareTo("exit")==0||tempString.compareTo("return")==0) {
                    return;
                }
                System.out.println("stuList");
                for(int i=0;i<students.size();i++) {
                    System.out.println("Student:"+students.get(i).toString());
                }
                System.out.println("empList");
                for(int i=0;i<employees.size();i++) {
                    System.out.println("Employee:"+employees.get(i).toString());
                }
                 
            }
        }
    }
}

7-42 jmu-Java-04面向對象進階-03-接口-自定義接口ArrayIntegerStack (10 分)

import java.util.LinkedList;
import java.util.Scanner;
interface IntegerStack{
    public Integer push(Integer item); //如item爲null，則不入棧直接返回null。否則直接入棧，然後返回item。
    public Integer pop();              //出棧，如棧爲空，則返回null。
    public Integer peek();             //獲得棧頂元素，如棧頂爲空，則返回null。注意：不要出棧
    public boolean empty();           //如過棧爲空返回true
    public int size();                //返回棧中元素數量
}
class ArrayListIntegerStack implements IntegerStack{
    LinkedList linkedList=new LinkedList();
    @Override
    public Integer push(Integer item) {
        if (item==null){
            return null;
        }
        linkedList.push(item);
        return item;
    }
    @Override
    public Integer pop() {
        if (linkedList.size()==0){
            return null;
        }
        return (int)linkedList.pop();
    }
    @Override

    public Integer peek() {

        if (linkedList.size()==0){

            return null;
        }
        return (int)linkedList.peek();
    }
    @Override
    public boolean empty() {
        return linkedList.isEmpty();
    }
    @Override
    public int size() {
        return linkedList.size();
    }
    @Override
    public String toString() {
        String s="";
        s+="[";
        int i=linkedList.size();
        if (i!=0){
            i--;
            for (;i>0;i--){
                s+=linkedList.get(i)+", ";
            }
            s+=linkedList.get(i)+"]";
        }else {
            s+="]";
        }
        return  s;
    }
}
public class Main {
    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        int num=sc.nextInt();
        ArrayListIntegerStack arrayListIntegerStack = new ArrayListIntegerStack();
        for (int i=0;i<num;i++){
            int number=sc.nextInt();
            System.out.println(arrayListIntegerStack.push(number));
        }
        System.out.println(arrayListIntegerStack.peek()+","+arrayListIntegerStack.empty()+","+arrayListIntegerStack.size());
        System.out.println(arrayListIntegerStack.toString());
        int pop_num=sc.nextInt();
        for (int i=0;i<pop_num;i++){
            System.out.println(arrayListIntegerStack.pop());
        }
        System.out.println(arrayListIntegerStack.peek()+","+arrayListIntegerStack.empty()+","+arrayListIntegerStack.size());
        System.out.println(arrayListIntegerStack.toString());
    }
}

7-43 jmu-Java-04面向對象進階-04-嵌套類-靜態嵌套類 (10 分)

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner in=new Scanner(System.in);
        int n=in.nextInt();

        double [] d=new double[n];
        for (int i=0;i<n;i++){
            d[i]=in.nextDouble();
        }
        System.out.println( ArrayUtils.findMinMax(d).toString());
        System.out.println(ArrayUtils.PairResult.class);
    }
}
class ArrayUtils {
    static class PairResult {
        private double min;
        private double max;

        public PairResult() {
        }
        public PairResult(double min, double max) {
            this.min = min;
            this.max = max;
        }

        @Override
        public String toString() {
            return "PairResult [" +
                    "min=" + min +
                    ", max=" + max +
                    ']';
        }
    }

    public static PairResult findMinMax(double[] values) {
        for (int i = 0; i < values.length - 1; i++) {
            //內存循環，是每一輪中進行的兩兩比較
            for (int j = 0; j < values.length - 1; j++) {
                if (values[j] > values[j + 1]) {
                    double temp = values[j];
                    values[j] = values[j + 1];
                    values[j + 1] = temp;
                }
            }
        }
        PairResult pairResult = new PairResult(values[0], values[values.length - 1]);
        return pairResult;
    }
}

7-44 jmu-Java-05集合-01-ArrayListIntegerStack (15 分)

import java.util.LinkedList;
import java.util.Scanner;
public class Main {

    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        ArrayIntegerStack a=new ArrayIntegerStack();
        int m=in.nextInt();
        for (int j=0;j<m;j++){
            int p=in.nextInt();
            System.out.println(a.push(p));
        }
        System.out.println(a.peek()+","+a.empty()+","+a.size());
        System.out.println( a.toString());


        int x=in.nextInt();
        for (int j=0;j<x;j++){
            System.out.println(a.pop());
        }
        System.out.println(a.peek()+","+a.empty()+","+a.size());
        System.out.println( a.toString());

    }
}
interface IntegerStack{
    //如果item爲null，則不入棧直接返回null。如果棧滿，也返回null。如果插入成功，返回item。
    public Integer push(Integer item);
    //出棧，如果爲空，則返回null。出棧時只移動棧頂指針，相應位置不置爲null
    public Integer pop();
    //獲得棧頂元素，如果爲空，則返回null.
    public Integer peek();
    //如果爲空返回true
    public boolean empty();
    //返回棧中元素個數
    public int size();
}
class ArrayIntegerStack implements IntegerStack {
    LinkedList arrayList = new LinkedList();
    @Override
    public Integer push(Integer item) {
        if (item == null) {
            return null;
        }
        arrayList.push(item);
        return item;
    }
    @Override
    public Integer pop() {
        if (arrayList.size()==0){
            return null;
        }
        return (int)arrayList.pop();
    }

    @Override
    public Integer peek() {
        if (arrayList.size()==0){
            return null;
        }
        return (int)arrayList.peek();
    }

    @Override
    public boolean empty() {
        return arrayList.isEmpty();
    }

    @Override
    public int size() {
        return arrayList.size();
    }

    @Override
    public String toString() {
        String s="";
         if (arrayList.size()==0){
             s+="[]";
         }else {
             s+="[";
             for (int i=arrayList.size()-1;i>=0;i--) {
                 if (i!=0) {
                     s+=arrayList.get(i) + ", ";

                 }else {
                    s+=arrayList.get(i);
                 }

             }
            s+="]";
         }
//         return arrayList.toString();
//        String s="";
//
//        s+="[";
//        int i=arrayList.size();
//        if (i!=0){
//            i--;
//            for (;i>0;i--){
//                s+=arrayList.get(i)+", ";
//            }
//            s+=arrayList.get(i)+"]";
//        }else {
//            s+="]";
//        }
        return  s;

    }
}

7-45 橫平豎直 (5 分)

import java.util.Scanner;
public class Main{
    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        int height, width;
        char status;
        height = in.nextInt();
        width = in.nextInt();
        Board board = new Board(height, width);
        status = board.getStatus();
        System.out.print(status);
    }
}
class Board{
    int height, width;
    public Board(int height, int width){
        this.height = height;
        this.width = width;
    }
    public char getStatus(){
        if(height<=width){
            return status(1);
        }else{
            return status(1.0);
        }
    }
    public char status(double rate){
           return 'B';
    }
    public char status(int rate){

     return 'A';
    }
}

7-46 集體評分 (5 分)

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int[] grade = new int[5];
        for(int i=0; i<grade.length; i++){
            grade[i] = in.nextInt();
        }

        RR rr = new RT(grade);
        double dd = rr.mark();
        System.out.printf("%.2f",dd);
    }
}
abstract class RR{
    int[] grade;
    public RR(int[] grade){
        this.grade = grade;
    }
    public abstract double mark();
}
class RT extends RR{
    public RT(int[] grade) {
        super(grade);
    }
    @Override
    public double mark() {
        double a=((grade[1]+grade[2]+grade[3])/3.0);
        return a;
    }
}

7-47 集體評分2 (5 分)

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int[] grade = new int[5];
        for(int i=0; i<grade.length; i++){
            grade[i] = in.nextInt();
        }

        RR rr = new RT(grade);
        double dd = rr.mark();
        System.out.printf("%.2f",dd);
    }
}
abstract class RR{
    int[] grade;
    public RR(int[] grade){
        this.grade = grade;
    }
    public abstract double mark();
}
class RT extends RR{
    public RT(int[] grade) {
        super(grade);
    }
    @Override
    public double mark() {
        double a=((grade[1]+grade[2]+grade[3])/3.0);
        return a;
    }
}

7-48 程序改錯題2 (5 分)

public class Main {
    public static void main(String[] args) {
        Animal animal = new Dog();
        animal.shout();
        ((Dog) animal).run();
    }
}

class Animal {
    void shout() {
        System.out.println("animal shout！");
    }
}

class Dog extends Animal {
    public void shout() {
        super.shout();
        System.out.println("wangwang……");
    }

    public void run() {
        System.out.println("Dog is running");
    }
}

7-49 程序填空題3 (5 分)

public class Main {
    public static void main(String[] args) {
        Son son = new Son(false);
        son.method();
    }
}

class Parent {
    Parent() {
        System.out.println("Parent's Constructor without parameter");
    }

    Parent(boolean b) {
        System.out.println("Parent's Constructor with a boolean parameter");
    }

    public void method() {
        System.out.println("Parent's method()");
    }
}

class Son extends Parent {
    public Son() {
        System.out.println("Son's Constructor without parameter");
    }

    @Override
    public void method() {
        System.out.println("Son's method()");
        super.method();
    }

    public Son(boolean b) {

        super(b);
        System.out.println("Son's Constructor without parameter");
    }
}

7-50 職工排序題 (20 分)

import java.util.*;

public class Main {
    public static void main(String[] args) {
        ArrayList <staff> arrayList=new ArrayList<staff>();
        staff [] s=new staff[5];
        s[0]=new staff(1,"職工1","female",500,400);
        s[1]=new staff(2,"職工2","female",400,600);
        s[2]=new staff(3,"職工3","male",600,300);
        s[3]=new staff(4,"職工4","female",800,200);
        s[4]=new staff(5,"職工5","male",500,700);
        for (int i=0;i<5;i++){
            arrayList.add(s[i]);
        }
        System.out.println("編號,團險,個險,姓名,性別");
        Collections.sort(arrayList);
        for (int j=0;j<arrayList.size();j++){
            System.out.println(arrayList.get(j).getId()+","+arrayList.get(j).getTeam()+","+arrayList.get(j).getPersonal()+","+arrayList.get(j).getName()+","+arrayList.get(j).getGender());
        }
        class Team implements Comparator<staff>{
            @Override
            public int compare(staff o1, staff o2) {
                return o1.getTeam()-o2.getTeam();
            }
        }
        System.out.println("編號,團險,個險,姓名,性別");
        Arrays.sort(s, new Team());
        for(staff i : s){
            System.out.println(i.getId()+","+i.getTeam()+","+i.getPersonal()+","+i.getName()+","+i.getGender());
        }
    }
}
class staff implements Comparable {
    private int id;
    private String name;
    private String gender;
    private int team;
    private int personal;

    public staff() {
    }

    public staff(int id, String name, String gender, int team, int personal) {
        this.id = id;
        this.name = name;
        this.gender = gender;
        this.team = team;
        this.personal = personal;
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public String getGender() {
        return gender;
    }

    public void setGender(String gender) {
        this.gender = gender;
    }

    public int getTeam() {
        return team;
    }

    public void setTeam(int team) {
        this.team = team;
    }

    public int getPersonal() {
        return personal;
    }

    public void setPersonal(int personal) {
        this.personal = personal;
    }

    @Override
    public int compareTo(Object o) {
          staff s=(staff)o;
        if((this.team+this.personal) < (((staff) o).personal+((staff) o).team))
            return -1;
        else if((this.team+this.personal) > (((staff) o).personal+((staff) o).team))
            return 1;
        else
            return 0;
    }

}

7-51 好玩的圖形 (20 分)

import java.text.DecimalFormat;
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        DecimalFormat df = new DecimalFormat("#.00");
        int n=in.nextInt();
        Shape [] shapes=new Shape[n];
        for (int i=0;i<n;i++) {
        int k=in.nextInt();
        if (k==1){
           float radius=in.nextFloat();
           Circle c=new Circle(radius);
           shapes[i]=c;
        }else {
            float w=in.nextFloat();
            float l=in.nextFloat();
            Tange t=new Tange(w,l);
            shapes[i]=t;
        }
        }
        for (int i=0;i<shapes.length;i++){
            System.out.println(df.format(shapes[i].getArea())+" "+df.format(shapes[i].getPerimeter()));
        }
    }
}
interface Shape{
    float getArea();//求面積
    float getPerimeter();//求周長
    double PI=3.1415926;
}
class Circle implements Shape{
    private float radius;

    public Circle(float radius) {
        this.radius = radius;
    }

    @Override
    public float getArea() {
       return  (float) PI*radius*radius;

    }

    @Override
    public float getPerimeter() {
        return (float)PI*2*radius;
    }
}
class Tange implements Shape{
    private float w;
    private float l;

    public Tange(float w, float l) {
        this.w = w;
        this.l = l;
    }

    @Override
    public float getArea() {
        return w*l;
    }

    @Override
    public float getPerimeter() {
        return 2*(w+l);
    }
}

7-52 jmu-Java-02基本語法-01-綜合小測驗 (4 分)

import java.util.Arrays;
import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        int [] s5=new int[1];
        while (true){
            String sc=in.nextLine();
            if (sc.equals("fib"))
            {
                String n=in.nextLine();
                for (int i=1;i<Integer.parseInt(n);i++){
                    System.out.print(fib(i)+" ");
                }
                System.out.println(fib(Integer.parseInt(n)));

            }else if (sc.equals("sort")){
                String s=in.nextLine();
                String[] s1=s.split(" ");
                s5=new int[s1.length];
                for (int i=0;i<s1.length;i++){
                   s5[i]=Integer.valueOf(s1[i]);
                }
                
                Arrays.sort(s5);
                System.out.println( Arrays.toString(s5));
            }else if (sc.equals("search")){
              String s=in.nextLine();
              int a= Arrays.binarySearch(s5,Integer.parseInt(s));
              if (a<0){
                  System.out.println(-1);
              }else {
                  System.out.println(a);
              }

            }else  if (sc.equals("getBirthDate"))
            {
              String n=in.nextLine();
              String [] c=new String[Integer.parseInt(n)];
              for (int i=0;i<Integer.parseInt(n);i++){
                  c[i]=in.nextLine();
                  String year=c[i].substring(6,c[i].length()-8);
                  String month=c[i].substring(10,c[i].length()-6);
                  String day=c[i].substring(12,c[i].length()-4);
                  System.out.println(year+"-"+month+"-"+day);
              }
            }else
            {
                System.out.println("exit");
                break;
            }
        }

    }
    public static int fib(int n){
        if(n==1 || n==2){
            return 1;
        }
        return fib(n-1) + fib(n-2);

    }
}

7-53 編程題：選修課成績統計問題-hebust (12 分)

import java.util.Scanner;
public class Main {
    public static void main(String[] args) {
      Scanner in=new Scanner(System.in);
      String s=in.nextLine();
      String []s1=s.split(",");
      for (int i=0;i<s1.length;i++){
          String []s2=s1[i].split(" ");
          int count=0;
          int num=0;
          for (int j=0;j<s2.length;j++){
              num++;
               if (s2[j].equals("A")){
                   count+=5;
               }else if (s2[j].equals("B")){
                   count+=4;
               }else if (s2[j].equals("C")){
                   count+=3;
               }else if (s2[j].equals("D")){
                   count+=2;
               }else if (s2[j].equals("E")){
                   count+=1;
               }
               if (num==3){
                   if (i==s1.length-1){
                       System.out.print(s2[0]+" "+count);
                   }else {
                       System.out.print(s2[0]+" "+count+",");
                   }
               }


          }
      }
    }
}

PTA練習

PTA總結

7-21 聲明長方體類，新增加成員變量：重量，並增加計算長方體表面積的函數。

7-22 聲明圖書類，記錄圖書總冊數，利用靜態變量賦值。

7-23 jmu-Java-03面向對象基礎-01-構造函數與toString (3 分)

7-25 jmu-Java-03面向對象基礎-03-形狀 (3 分)

7-26 構造方法 (5 分)

7-27 構造方法 (5 分)

7-28 平均壽命 (5 分)

7-29 定義類 (5 分)

7-30 定義類2 (5 分)

7-31 計算年齡 (10 分)

7-32 程序改錯題3 (5 分)

7-33 程序填空題1 (5 分)

7-34 程序填空題2 (5 分)

7-35 類的定義與對象使用 (10 分)

7-36 sdust-Java-學生成績讀取與排序 (10 分)

7-37 定義ClassName接口，設計類Company，實現獲取類名稱的功能 (10 分)

7-38 jmu-Java-03面向對象基礎-04-形狀-繼承 (15 分)

7-39 jmu-Java-03面向對象基礎-05-覆蓋 (3 分)

7-40 jmu-Java-04面向對象進階–02-接口-Comparator (5 分)

7-41 jmu-Java-03面向對象-06-繼承覆蓋綜合練習-Person、Student、Employee、Company (15 分)

7-42 jmu-Java-04面向對象進階-03-接口-自定義接口ArrayIntegerStack (10 分)

7-43 jmu-Java-04面向對象進階-04-嵌套類-靜態嵌套類 (10 分)

7-44 jmu-Java-05集合-01-ArrayListIntegerStack (15 分)

7-45 橫平豎直 (5 分)

7-46 集體評分 (5 分)

7-47 集體評分2 (5 分)

7-48 程序改錯題2 (5 分)

7-49 程序填空題3 (5 分)

7-50 職工排序題 (20 分)

7-51 好玩的圖形 (20 分)

7-52 jmu-Java-02基本語法-01-綜合小測驗 (4 分)

7-53 編程題：選修課成績統計問題-hebust (12 分)