狄慧201771010104《面向对象程序设计（java）》第十一周学习总结

实验十一集合

实验时间 2018-11-8

1、实验目的与要求

(1) 掌握Vetor、Stack、Hashtable三个类的用途及常用API；

(2) 了解java集合框架体系组成；

(3) 掌握ArrayList、LinkList两个类的用途及常用API。

(4) 了解HashSet类、TreeSet类的用途及常用API。

(5)了解HashMap、TreeMap两个类的用途及常用API；

(6) 结对编程（Pair programming）练习，体验程序开发中的两人合作。

2、实验内容和步骤

实验1：导入第9章示例程序，测试程序并进行代码注释。

测试程序1：

l 使用JDK命令运行编辑、运行以下三个示例程序，结合运行结果理解程序；

l 掌握Vetor、Stack、Hashtable三个类的用途及常用API。

//示例程序1

import java.util.Vector;

class Cat {

private int catNumber;

Cat(int i) {

catNumber = i;

}

void print() {

System.out.println("Cat #" + catNumber);

}

class Dog {

private int dogNumber;

Dog(int i) {

dogNumber = i;

}

void print() {

System.out.println("Dog #" + dogNumber);

}

public class CatsAndDogs {

public static void main(String[] args) {

Vector cats = new Vector();

for (int i = 0; i < 7; i++)

cats.addElement(new Cat(i));

cats.addElement(new Dog(7));

for (int i = 0; i < cats.size(); i++)

((Cat) cats.elementAt(i)).print();

}

//示例程序2

import java.util.*;

public class Stacks {

static String[] months = { "1", "2", "3", "4" };

public static void main(String[] args) {

Stack stk = new Stack();

for (int i = 0; i < months.length; i++)

stk.push(months[i]);

System.out.println(stk);

System.out.println("element 2=" + stk.elementAt(2));

while (!stk.empty())

System.out.println(stk.pop());

}

//示例程序3

import java.util.*;

class Counter {

int i = 1;

public String toString() {

return Integer.toString(i);

}

public class Statistics {

public static void main(String[] args) {

Hashtable ht = new Hashtable();

for (int i = 0; i < 10000; i++) {

Integer r = new Integer((int) (Math.random() * 20));

if (ht.containsKey(r))

((Counter) ht.get(r)).i++;

else

ht.put(r, new Counter());

}

System.out.println(ht);

}

import java.util.Vector;//实现自动增长的对象数组

class Cat {
    private int catNumber;

    Cat(int i) {
        catNumber = i;
    }

    void print() {
        System.out.println("Cat #" + catNumber);
    }
}

class Dog {
    private int dogNumber;

    Dog(int i) {
        dogNumber = i;
    }

    void print() {
        System.out.println("Dog #" + dogNumber);
    }
}

public class CatsAndDogs {
    public static void main(String[] args) {
        Vector cats = new Vector();
        for (int i = 0; i < 7; i++)
            cats.addElement(new Cat(i));
        cats.addElement(new Dog(7));
        for (int i = 0; i < cats.size(); i++)
            if (cats.elementAt(i) instanceof Cat) //判断是否能进行强制类型转换
            {
                ((Cat) cats.elementAt(i)).print();//能进行强制类型转换，输出为Cat型
            } else {
                ((Dog) cats.elementAt(i)).print();//不能进行强制类型转化，输出为Dog型
            }
    }
}

//示例程序2
import java.util.*;
 
public class Stacks {
    static String[] months = { "1", "2", "3", "4" };
 
    public static void main(String[] args) {
        Stack stk = new Stack();
        for (int i = 0; i < months.length; i++)
            stk.push(months[i]);//入栈
        System.out.println(stk);
        System.out.println("element 2=" + stk.elementAt(2));//因为class Stack<E> extends Vector<E>所以可以使用elementAt来定位
        while (!stk.empty())
            System.out.println(stk.pop());//判断如果栈不空，进行出栈操作（先进后出）
    }
}

//示例程序3
import java.util.*;
 
class Counter {
    int i = 1;
 
    public String toString() {
        return Integer.toString(i);
    }
}
 
public class Statistics {
    public static void main(String[] args) {
        Hashtable ht = new Hashtable();
        for (int i = 0; i < 10000; i++) {
            Integer r = new Integer((int) (Math.random() * 20));//r此时为键值范围（0~19）
            if (ht.containsKey(r))
                ((Counter) ht.get(r)).i++;//得到相应的value
            else
                ht.put(r, new Counter());//如果键值不同则重新创建
        }
        System.out.println(ht);
    }
}

测试程序2：

l 使用JDK命令编辑运行ArrayListDemo和LinkedListDemo两个程序，结合程序运行结果理解程序；

import java.util.*;

public class ArrayListDemo {

public static void main(String[] argv) {

ArrayList al = new ArrayList();

// Add lots of elements to the ArrayList...

al.add(new Integer(11));

al.add(new Integer(12));

al.add(new Integer(13));

al.add(new String("hello"));

// First print them out using a for loop.

System.out.println("Retrieving by index:");

for (int i = 0; i < al.size(); i++) {

System.out.println("Element " + i + " = " + al.get(i));

}

import java.util.*;

public class LinkedListDemo {

public static void main(String[] argv) {

LinkedList l = new LinkedList();

l.add(new Object());

l.add("Hello");

l.add("zhangsan");

ListIterator li = l.listIterator(0);

while (li.hasNext())

System.out.println(li.next());

if (l.indexOf("Hello") < 0)

System.err.println("Lookup does not work");

else

System.err.println("Lookup works");

}

l 在Elipse环境下编辑运行调试教材360页程序9-1，结合程序运行结果理解程序；

l 掌握ArrayList、LinkList两个类的用途及常用API。

import java.util.*;

public class ArrayListDemo {

public static void main(String[] argv) {

ArrayList al = new ArrayList();

al.add(new Integer(11));

al.add(new Integer(12));

al.add(new Integer(13));

al.add(new String("hello"));

//包装类即使把基本类型变成对象类型  像ArrayList这样的集合是不能储存基本类型的只能储存对象 为了方便这些集合的使用所以才有了把基本类型包装成对象类型

System.out.println("Retrieving by index:");

for (int i = 0; i < al.size(); i++)

{

System.out.println("Element " + i + " = " + al.get(i));

}

import java.util.*;
public class LinkedListDemo {
    public static void main(String[] argv) {
        LinkedList l = new LinkedList();
        l.add(new Object());
        l.add("Hello");
        l.add("zhangsan");
        ListIterator li = l.listIterator(0);//ListIterator<E> extends Iterator<E>迭代器
        while (li.hasNext())
            System.out.println(li.next());
        if (l.indexOf("Hello") < 0)   
            System.err.println("Lookup does not work");
        else
            System.err.println("Lookup works");
   }
}

测试程序3：

l 运行SetDemo程序，结合运行结果理解程序；

import java.util.*;

public class SetDemo {

public static void main(String[] argv) {

HashSet h = new HashSet(); //也可以 Set h=new HashSet()

h.add("One");

h.add("Two");

h.add("One"); // DUPLICATE

h.add("Three");

Iterator it = h.iterator();

while (it.hasNext()) {

System.out.println(it.next());

}

l 在Elipse环境下调试教材365页程序9-2，结合运行结果理解程序；了解HashSet类的用途及常用API。

l 在Elipse环境下调试教材367页-368程序9-3、9-4，结合程序运行结果理解程序；了解TreeSet类的用途及常用API。

import java.util.HashSet;
import java.util.Iterator;
public class SetDemo {
    public static void main(String[] argv) {
        HashSet h = new HashSet(); //也可以 Set h=new HashSet(),Hashset实现了Set接口
        h.add("One");
        h.add("Two");
        h.add("Four"); 
        h.add("Three");
        Iterator it = h.iterator();
        while (it.hasNext()) //hasnext检查是否还有元素进行遍历
        {
             System.out.println(it.next());
        }
    }
}

package treeSet;
 
import java.util.*;
 
/**
 * An item with a description and a part number.
 */
public class Item implements Comparable<Item>//实现比较接口
{
   private String description;
   private int partNumber;
 
   /**
    * Constructs an item.
    * 
    * @param aDescription
    *           the item's description
    * @param aPartNumber
    *           the item's part number
    */
   public Item(String aDescription, int aPartNumber)
   {
      description = aDescription;
      partNumber = aPartNumber;
   }
 
   /**
    * Gets the description of this item.
    * 
    * @return the description
    */
   public String getDescription()
   {
      return description;
   }
 
   public String toString()
   {
      return "[description=" + description + ", partNumber=" + partNumber + "]";
   }
 
   public boolean equals(Object otherObject)
   {
      if (this == otherObject) return true;
      if (otherObject == null) return false;
      if (getClass() != otherObject.getClass()) return false;
      Item other = (Item) otherObject;
      return Objects.equals(description, other.description) && partNumber == other.partNumber;
   }
 
   public int hashCode()
   {
      return Objects.hash(description, partNumber);
   }
 
   public int compareTo(Item other)
   {
      int diff = Integer.compare(partNumber, other.partNumber);
      return diff != 0 ? diff : description.compareTo(other.description);
   }
}

package treeSet;
 
import java.util.*;
 
/**
 * This program sorts a set of item by comparing their descriptions.
 * @version 1.12 2015-06-21
 * @author Cay Horstmann
 */
public class TreeSetTest
{
   public static void main(String[] args)
   {
      SortedSet<Item> parts = new TreeSet<>();
      parts.add(new Item("Toaster", 1234));
      parts.add(new Item("Widget", 4562));
      parts.add(new Item("Modem", 9912));
      System.out.println(parts);
 
      NavigableSet<Item> sortByDescription = new TreeSet<>(
            Comparator.comparing(Item::getDescription));//吧自定义类对象放到Treeset排序
 
      sortByDescription.addAll(parts);
      System.out.println(sortByDescription);
   }
}

测试程序4：

l 使用JDK命令运行HashMapDemo程序，结合程序运行结果理解程序；

import java.util.*;

public class HashMapDemo {

public static void main(String[] argv) {

HashMap h = new HashMap();

// The hash maps from company name to address.

h.put("Adobe", "Mountain View, CA");

h.put("IBM", "White Plains, NY");

h.put("Sun", "Mountain View, CA");

String queryString = "Adobe";

String resultString = (String)h.get(queryString);

System.out.println("They are located in: " + resultString);

}

import java.util.*;
public class HashMapDemo {
   public static void main(String[] argv) {
      HashMap h = new HashMap();
      
      h.put("Adobe", "Mountain View, CA");
      h.put("IBM", "White Plains, NY");
      h.put("Sun", "Mountain View, CA");
      String queryString = "IBM";
      String resultString = (String) h.get(queryString);//get用来获得value值(以键值为参数）
      System.out.println("They are located in: " +  resultString);
   }
}

l 在Elipse环境下调试教材373页程序9-6，结合程序运行结果理解程序；

l 了解HashMap、TreeMap两个类的用途及常用API。

package map;
 
import java.util.*;
 
/**
 * This program demonstrates the use of a map with key type String and value type Employee.
 * @version 1.12 2015-06-21
 * @author Cay Horstmann
 */
public class MapTest
{
   public static void main(String[] args)
   {
      Map<String, Employee> staff = new HashMap<>();
      staff.put("144-25-5464", new Employee("Amy Lee"));
      staff.put("567-24-2546", new Employee("Harry Hacker"));
      staff.put("157-62-7935", new Employee("Gary Cooper"));
      staff.put("456-62-5527", new Employee("Francesca Cruz"));
 
      // 打印所有条目
      System.out.println(staff);
 
      // 删除一个项目
 
      staff.remove("567-24-2546");
 
      // replace an entry
 
      staff.put("456-62-5527", new Employee("Francesca Miller"));
 
      // 浏览一个值
 
      System.out.println(staff.get("157-62-7935"));
 
      // 迭代遍历
 
      staff.forEach((k, v) -> 
         System.out.println("key=" + k + ", value=" + v));
   }
}

实验2：结对编程练习：

l 关于结对编程：以下图片是一个结对编程场景：两位学习伙伴坐在一起，面对着同一台显示器，使用着同一键盘，同一个鼠标，他们一起思考问题，一起分析问题，一起编写程序。

l 关于结对编程的阐述可参见以下链接：

http://www.cnblogs.com/xinz/archive/2011/08/07/2130332.html

http://en.wikipedia.org/wiki/Pair_programming

l 对于结对编程中代码设计规范的要求参考：

http://www.cnblogs.com/xinz/archive/2011/11/20/2255971.html

以下实验，就让我们来体验一下结对编程的魅力。

l 确定本次实验结对编程合作伙伴；李瑞红

l 各自运行合作伙伴实验九编程练习1，结合使用体验对所运行程序提出完善建议；

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Scanner;
import java.util.Collections;//对集合进行排序、查找、修改等；

public class Test {
    private static ArrayList<Citizen> citizenlist;

    public static void main(String[] args) {
        citizenlist = new ArrayList<>();
        Scanner scanner = new Scanner(System.in);
        File file = new File("E:/java/身份证号.txt");
        //异常捕获
        try {
            FileInputStream fis = new FileInputStream(file);
            BufferedReader in = new BufferedReader(new InputStreamReader(fis));
            String temp = null;
            while ((temp = in.readLine()) != null) {

                Scanner linescanner = new Scanner(temp);

                linescanner.useDelimiter(" ");
                String name = linescanner.next();
                String id = linescanner.next();
                String sex = linescanner.next();
                String age = linescanner.next();
                String birthplace = linescanner.nextLine();
                Citizen citizen = new Citizen();
                citizen.setName(name);
                citizen.setId(id);
                citizen.setSex(sex);
                // 将字符串转换成10进制数
                int ag = Integer.parseInt(age);
                citizen.setage(ag);
                citizen.setBirthplace(birthplace);
                citizenlist.add(citizen);

            }
        } catch (FileNotFoundException e) {
            System.out.println("信息文件找不到");
            e.printStackTrace();
        } catch (IOException e) {
            System.out.println("信息文件读取错误");
            e.printStackTrace();
        }
        boolean isTrue = true;
        while (isTrue) {

            System.out.println("1.按姓名字典序输出人员信息");
            System.out.println("2.查询最大年龄的人员信息、查询最小年龄人员信息");
            System.out.println("3.查询人员中是否查询人员中是否有你的同乡");
            System.out.println("4.输入你的年龄，查询文件中年龄与你最近人的姓名、身份证号、年龄、性别和出生地");
            System.out.println("5.退出");
            int nextInt = scanner.nextInt();
            switch (nextInt) {
            case 1:
                Collections.sort(citizenlist);
                System.out.println(citizenlist.toString());
                break;
            case 2:
                int max = 0, min = 100;
                int m, k1 = 0, k2 = 0;
                for (int i = 1; i < citizenlist.size(); i++) {
                    m = citizenlist.get(i).getage();
                    if (m > max) {
                        max = m;
                        k1 = i;
                    }
                    if (m < min) {
                        min = m;
                        k2 = i;
                    }
                }
                System.out.println("年龄最大：" + citizenlist.get(k1));
                System.out.println("年龄最小：" + citizenlist.get(k2));
                break;
            case 3:
                System.out.println("出生地：");
                String find = scanner.next();
                String place = find.substring(0, 3);
                for (int i = 0; i < citizenlist.size(); i++) {
                    if (citizenlist.get(i).getBirthplace().substring(1, 4).equals(place))
                        System.out.println("出生地" + citizenlist.get(i));
                }
                break;
            case 4:
                System.out.println("年龄：");
                int yourage = scanner.nextInt();
                int near = peer(yourage);
                int j = yourage - citizenlist.get(near).getage();
                System.out.println("" + citizenlist.get(near));
                break;
            case 5:
                isTrue = false;
                System.out.println("程序已退出!");
                break;
            default:
                System.out.println("输入有误");
            }
        }
    }

    public static int peer(int age) {
        int flag = 0;
        int min = 53, j = 0;
        for (int i = 0; i < citizenlist.size(); i++) {
            j = citizenlist.get(i).getage() - age;
            if (j < 0)
                j = -j;
            if (j < min) {
                min = j;
                flag = i;
            }
        }
        return flag;
    }
}

public class Citizen implements Comparable<Citizen> {

    private String name;
    private String id;
    private String sex;
    private int age;
    private String birthplace;

    public String getName() {
        return name;
    }

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

    public String getId() {
        return id;
    }

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

    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public int getage() {
        return age;
    }

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

    public String getBirthplace() {
        return birthplace;
    }

    public void setBirthplace(String birthplace) {
        this.birthplace = birthplace;
    }

    public int compareTo(Citizen other) {
        return this.name.compareTo(other.getName());
    }

    public String toString() {
        return name + "	" + sex + "	" + age + "	" + id + "	" + birthplace + "
";
    }
}

l 各自运行合作伙伴实验十编程练习2，结合使用体验对所运行程序提出完善建议；

import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.util.Scanner;

/*
 * 该程序用来随机生成0到100以内的加减乘除题
 */
public class Demo {
    public static void main(String[] args) {
        // 用户的答案要从键盘输入，因此需要一个键盘输入流
        Scanner in = new Scanner(System.in);
        Counter counter = new Counter();
        PrintWriter out = null;
        try {
            out = new PrintWriter("text.txt");
        } catch (FileNotFoundException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        // 定义一个变量用来统计得分
        int sum = 0;
        int k = 0;
        // 通过循环生成10道题
        for (int i = 0; i < 10; i++) {

            // 随机生成两个100以内的随机数作加减乘除
            int a = (int) Math.round(Math.random() * 100);
            int b = (int) Math.round(Math.random() * 100);
            int d = (int) Math.round(Math.random() * 3);

            switch (d) {

            case 0:
                if (a % b == 0) {
                    System.out.println(a + "/" + b + "=");
                    break;
                }
                 int c = in.nextInt();
                 out.println(a + "/" + b + "="+c);
            case 1:
                System.out.println(a + "*" + b + "=");
                 int c1 = in.nextInt();
                 out.println(a + "*" + b + "="+c1);
                break;
            case 2:
                System.out.println(a + "+" + b + "=");
                 int c2 = in.nextInt();
                 out.println(a + "+" + b + "="+c2);
                break;
            case 3:
                if (a > b) {
                    System.out.println(a + "-" + b + "=");
                    break;
                }
                 int c3 = in.nextInt();
               out.println(a + "-" + b + "="+c3);

            }

            // 定义一个整数用来接收用户输入的答案
            double c = in.nextDouble();

            // 判断用户输入的答案是否正确，正确给10分，错误不给分
            if (c == a / b | c == a * b | c == a + b | c == a - b) {
                sum += 10;
                System.out.println("恭喜答案正确");
            } else {
                System.out.println("抱歉，答案错误");

            }
            out.println(a + "/" + b + "=" + c);
            out.println(a + "*" + b + "=" + c);
            out.println(a + "+" + b + "=" + c);
            out.println(a + "-" + b + "=" + c);

        }
        // 输出用户的成绩
        System.out.println("你的得分为" + sum);

        out.println("成绩:" + sum);
        out.close();
    }
}

public class Counter {
    private int a;
    private int b;

    public int add(int a, int b) {
        return a + b;
    }

    public int reduce(int a, int b) {
        return a - b;
    }

    public int multiplication(int a, int b) {
        return a * b;
    }

    public int division(int a, int b) {
        if (b != 0)
            return a / b;
        else
            return 0;
    }

}

l 采用结对编程方式，与学习伙伴合作完成实验九编程练习1；

import java.io.BufferedReader;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.Collections;
import java.util.Scanner;


public class A{
    private static ArrayList<Test> studentlist;
    public static void main(String[] args) {
        studentlist = new ArrayList<>();
        Scanner scanner = new Scanner(System.in);
        File file = new File("D:\身份证号.txt");
        try {
            FileInputStream fis = new FileInputStream(file);
            BufferedReader in = new BufferedReader(new InputStreamReader(fis));
            String temp = null;
            while ((temp = in.readLine()) != null) {
                
                Scanner linescanner = new Scanner(temp);
                
                linescanner.useDelimiter(" ");    
                String name = linescanner.next();
                String number = linescanner.next();
                String sex = linescanner.next();
                String age = linescanner.next();
                String province =linescanner.nextLine();
                Test student = new Test();
                student.setName(name);
                student.setnumber(number);
                student.setsex(sex);
                int a = Integer.parseInt(age);
                student.setage(a);
                student.setprovince(province);
                studentlist.add(student);

            }
        } catch (FileNotFoundException e) {
            System.out.println("学生信息文件找不到");
            e.printStackTrace();
        } catch (IOException e) {
            System.out.println("学生信息文件读取错误");
            e.printStackTrace();
        }
        boolean isTrue = true;
        while (isTrue) {
           
            System.out.println("1:字典排序");
            System.out.println("2:输出年龄最大和年龄最小的人");
            System.out.println("3:寻找老乡");
            System.out.println("4:寻找年龄相近的人");
            System.out.println("5:退出");
            String m = scanner.next();
            switch (m) {
            case "1":
                Collections.sort(studentlist);              
                System.out.println(studentlist.toString());
                break;
            case "2":
                 int max=0,min=100;
                 int j,k1 = 0,k2=0;
                 for(int i=1;i<studentlist.size();i++)
                 {
                     j=studentlist.get(i).getage();
                 if(j>max)
                 {
                     max=j; 
                     k1=i;
                 }
                 if(j<min)
                 {
                   min=j; 
                   k2=i;
                 }
                 
                 }  
                 System.out.println("年龄最大："+studentlist.get(k1));
                 System.out.println("年龄最小："+studentlist.get(k2));
                break;
            case "3":
                 System.out.println("province?");
                 String find = scanner.next();        
                 String place=find.substring(0,3);
                 for (int i = 0; i <studentlist.size(); i++) 
                 {
                     if(studentlist.get(i).getprovince().substring(1,4).equals(place)) 
                         System.out.println("province"+studentlist.get(i));
                 }             
                 break;
                 
            case "4":
                System.out.println("年龄：");
                int yourage = scanner.nextInt();
                int near=agematched(yourage);
                int value=yourage-studentlist.get(near).getage();
                System.out.println(""+studentlist.get(near));
                break;
            case "5":
                isTrue = false;
                System.out.println("退出程序!");
                break;
                default:
                System.out.println("输入有误");

            }
        }
    }
        public static int agematched(int age) {      
        int j=0,min=53,value=0,k=0;
         for (int i = 0; i < studentlist.size(); i++)
         {
             value=studentlist.get(i).getage()-age;
             if(value<0) value=-value; 
             if (value<min) 
             {
                min=value;
                k=i;
             } 
          }    
         return k;         
      }

}

public  class Test implements Comparable<Test> {

    private String name;
    private String number ;
    private String sex ;
    private int age;
    private String province;
   
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public String getnumber() {
        return number;
    }
    public void setnumber(String number) {
        this.number = number;
    }
    public String getsex() {
        return sex ;
    }
    public void setsex(String sex ) {
        this.sex =sex ;
    }
    public int getage() {

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

    public String getprovince() {
        return province;
    }
    public void setprovince(String province) {
        this.province=province ;
    }

    public int compareTo(Test o) {
       return this.name.compareTo(o.getName());
    }

    public String toString() {
        return  name+"	"+sex+"	"+age+"	"+number+"	"+province+"
";
    }
    
}

l 采用结对编程方式，与学习伙伴合作完成实验十编程练习2。

package fghjg;
import java.util.Random;
import java.util.Scanner;

import java.io.FileNotFoundException;

import java.io.PrintWriter;

public class Main{
    public static void main(String[] args)
    {
        
        yunsuan counter=new yunsuan();//与其它类建立联系
    PrintWriter out=null;
    try {
        out=new PrintWriter("D:/text.txt");//将文件里的内容读入到D盘名叫text的文件中
         
    }catch(FileNotFoundException e) {
        System.out.println("文件找不到");
        e.printStackTrace();
    }
    
    
    int sum=0;

    for(int i=0;i<10;i++)
    {
    int a=new Random().nextInt(100);
    int b=new Random().nextInt(100);
    Scanner in=new Scanner(System.in);
    //in.close();
    
    switch((int)(Math.random()*4))
    
    {
    
    case 0:
        System.out.println( ""+a+"+"+b+"=");
        
        int c1 = in.nextInt();
        out.println(a+"+"+b+"="+c1);
        if (c1 == counter.plus(a, b)) {
            sum += 10;
            System.out.println("答案正确");
        }
        else {
            System.out.println("答案错误");
        }
        
        break ;
    case 1:
        if(a<b)
                        {
                                 int temp=a;
                                 a=b;
                                 b=temp;
                             }//为避免减数比被减数大的情况

         System.out.println(""+a+"-"+b+"=");
         /*while((a-b)<0)
         {  
             b = (int) Math.round(Math.random() * 100);
             
         }*/
        int c2 = in.nextInt();
        
        out.println(a+"-"+b+"="+c2);
        if (c2 == counter.minus(a, b)) {
            sum += 10;
            System.out.println("答案正确");
        }
        else {
            System.out.println("答案错误");
        }
         
        break ;
    
      

    
    case 2:
        
         System.out.println(""+a+"*"+b+"=");
        int c = in.nextInt();
        out.println(a+"*"+b+"="+c);
        if (c == counter.multiply(a, b)) {
            sum += 10;
            System.out.println("答案正确");
        }
        else {
            System.out.println("答案错误");
        }
        break;
    case 3:
        
        
         
        while(b==0)
        {  b = (int) Math.round(Math.random() * 100);//满足分母不为0
        }
        while(a%b!=0)
        {
              a = (int) Math.round(Math.random() * 100);
              b = (int) Math.round(Math.random() * 100);
        }
        System.out.println(""+a+"/"+b+"=");
     int c0= in.nextInt();
    
     out.println(a+"/"+b+"="+c0);
     if (c0 == counter.divide(a, b)) {
         sum += 10;
         System.out.println("答案正确");
     }
     else {
         System.out.println("答案错误");
     }
    
     break;
     

    }
    }
    System.out.println("totlescore:"+sum);
    out.println(sum);
    
    out.close();
    }
    }

package fghjg;
public class yunsuan <T>{
    private T a;
    private T b;
    public void yunsaun()
    {
        a=null;
        b=null;
    }
    public void yunsuan(T a,T b)
    {
        this.a=a;
        this.b=b;
    }
   public int plus(int a,int b)
   {
       return a+b;
       
   }
   public int minus(int a,int b)
   {
    return a-b;
       
   }
   public int multiply(int a,int b)
   {
       return a*b;
   }
   public int divide(int a,int b)
   {
       if(b!=0  && a%b==0)
       return a/b;
       else
           return 0;
   }
   }

实验总结：

通过本周学习，我复习了一些有关数据结构的知识，另外初步了解了java集合类，也了解了Vector类，Stack类以及Hashtable类。除此以外，本次实验第一次采用结对编程的方法，我通过和合作伙伴互相运行程序，相互讨论交流，从中学到了很多东西。也希望以后多采取这种方法，在合作中互相学习进步。