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。
java中的Iterator功能比较简单，并且只能单向移动：
(1) 使用方法iterator()要求容器返回一个Iterator。第一次调用Iterator的next()方法时，它返回序列的第一个元素。注意：iterator()方法是java.lang.Iterable接口,被Collection继承。
(2) 使用next()获得序列中的下一个元素。
(3) 使用hasNext()检查序列中是否还有元素。
(4) 使用remove()将迭代器新返回的元素删除。
HashSet的一些常用方法：
添加元素：
hashset.add(E e)：返回boolean型，如果此 set 中尚未包含指定元素，则添加指定元素；如果此 set 已包含该元素，则该调用不更改 set 并返回
false。
删除元素：
hashset.clear()：从此 set 中移除所有元素。
hashset.remove(Object o)：如果指定元素存在于此 set 中，则将其移除。
hashset.isEmpty()：如果此 set 不包含任何元素，则返回
true。
hashset.contains(Object o)：如果此 set 包含指定元素，则返回
true。
hashset.size()：返回此 set 中的元素的数量（set 的容量）。
Set 接口继承 Collection，但不允许重复，使用自己内部的一个排列机制。
List 接口继承 Collection，允许重复，以元素安插的次序来放置元素，不会重新排列。
Map接口是一组成对的键－值对象，即所持有的是key-value pairs。Map中不能有重复的key。拥有自己的内部排列机制。
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；
//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();//创建矢量类对象
for (int i = 0; i < 7; i++)
cats.addElement(new Cat(i));//用矢量类的API：addElement()添加元素
cats.addElement(new Dog(7));//添加第八个Dog类元素
for (int i = 0; i < cats.size()-1; i++)//此时cats的长度为8，而cat类对象只有7个
((Cat) cats.elementAt(i)).print();//用矢量类的API：elementAt（利用下表索引）找到元素
((Dog) cats.elementAt(7)).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]);//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);
}
}
l 掌握Vetor、Stack、Hashtable三个类的用途及常用API。
Vector类类似长度可变的数组，Vector中只能存放对象，Vector的元素通过下标进行访问。
Stack类是Vector的子类，Stack类描述堆栈数据结构。
Hashtable用一个特殊的值来确定键，名为hashcode（散列码）。所有对象都有一个散列码，可以通过Object类的hashCode()方法获得。
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；测试程序2：
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");
}
}
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。
package linkedList;
import java.util.*;
/**
* This program demonstrates operations on linked lists.
* @version 1.11 2012-01-26
* @author Cay Horstmann
*/
public class LinkedListTest
{
public static void main(String[] args)
{
List<String> a = new LinkedList<>();
a.add("Amy");
a.add("Carl");
a.add("Erica");
List<String> b = new LinkedList<>();
b.add("Bob");
b.add("Doug");
b.add("Frances");
b.add("Gloria");
// merge the words from b into a
ListIterator<String> aIter = a.listIterator();
Iterator<String> bIter = b.iterator();
while (bIter.hasNext())
{
if (aIter.hasNext())
aIter.next();
aIter.add(bIter.next());//将aIler和biter对象按其下表索引值依次遍历
}
System.out.println(a);
// 从b里面移除每一轮循环的第二个元素
bIter = b.iterator();
while (bIter.hasNext())
{
bIter.next(); //跳过第一个元素
if (bIter.hasNext())
{
bIter.next(); // skip next element
bIter.remove(); // remove that element
}
}
System.out.println(b);//此时b中元素只有两个
a.removeAll(b);//从a里面移除当前b中元素
System.out.println(a);
}
}
测试程序3：
l 运行SetDemo程序，结合运行结果理解程序；
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());
}
}
}
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。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。
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();
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 了解HashMap、TreeMap两个类的用途及常用API。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；
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：孔维滢
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.Collections;
import java.util.Scanner;
public class Identify {
private static ArrayList<Person> personlist;
public static void main(String[] args) {
personlist = new ArrayList<>();
Scanner scanner = new Scanner(System.in);
File file = new File("E:\\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 hometown = linescanner.nextLine();
Person person = new Person();
person.setName(name);
person.setnumber(number);
person.setsex(sex);
int A = Integer.parseInt(age);
person.setage(A);
person.sethometown(hometown);
personlist.add(person);
}
} catch (FileNotFoundException e) {
System.out.println("身份信息文件找不到");
e.printStackTrace();
} catch (IOException e) {
System.out.println("身份信息文件读取错误");
e.printStackTrace();
}
boolean isTrue = true;
while (isTrue) {
System.out.println("0.按姓名字典序输出人员信息；");
System.out.println("1.查询最大年龄人员信息；；");
System.out.println("2.查询最小年龄人员信息；");
System.out.println("3.寻找同乡；");
System.out.println("4.寻找年龄相近的人；");
System.out.println("5.退出。");
String W = scanner.next();
switch(W) {
case "0":
Collections.sort(personlist);
System.out.println(personlist.toString());
break;
case "1":
int a = 0;
int j, c1 = 0, d1 = 0;
for (int i = 1; i < personlist.size(); i++) {
j = personlist.get(i).getage();
if (j > a) {
a = j;
c1 = i;
}
}
System.out.println("年龄最大：" + personlist.get(c1));
break;
case "2":
int b = 100;
int j1,c2 = 0,d2 = 0;
for (int i = 1; i < personlist.size(); i++) {
j1 = personlist.get(i).getage();
if (j1 < b) {
b = j1;
d2 = i;
}
}
System.out.println("年龄最小：" + personlist.get(d2));
break;
case "3":
System.out.println("籍贯：");
String search = scanner.next();
String place = search.substring(0, 3);
int i = 0;
for (; i < personlist.size(); i++) {
if (personlist.get(i).gethometown().substring(1, 4).equals(place))
System.out.println("你的同乡是：" + personlist.get(i));
}
break;
case "4":
System.out.println("年龄：");
int yourage = scanner.nextInt();
int nearaga = agenear(yourage);
int value = yourage - personlist.get(nearaga).getage();
System.out.println("" + personlist.get(nearaga));
break;
case "5":
isTrue = false;
System.out.println("退出程序!");
break;
default:
System.out.println("检查输入！");
}
}
}
public static int agenear(int age) {
int j = 0, b = 53, value = 0, c = 0;
for (int i = 0; i < personlist.size(); i++) {
value = personlist.get(i).getage() - age;
if (value < 0)
value = -value;
if (value < b) {
b = value;
c = i;
}
}
return c;
}
}
public class Person implements Comparable<Person> {
private String name;
private String number;
private String sex;
private int age;
private String hometown;
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 gethometown() {
return hometown;
}
public void sethometown(String hometown) {
this.hometown = hometown;
}
public int compareTo(Person o) {
return this.name.compareTo(o.getName());
}
public String toString() {
return name + " " + sex + " " + age + " " + number + " " + hometown + "\n";
}
}
她对文件的操作比我的更加简洁明了，值得借鉴
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
package 计算器;
import java.io.FileNotFoundException;
import java.io.PrintWriter;
import java.util.Random;
import java.util.Scanner;
public class Studentexam {
public static void main(String[] args) {
Scanner in = new Scanner(System.in);
Studentexam s = new Studentexam();
PrintWriter out = null;
try {
out = new PrintWriter("test.txt");
} catch (FileNotFoundException e) {
System.out.println("文件输出失败");
e.printStackTrace();
}
int sum = 0;
for (int i = 1; i <= 10; i++) {
int a = (int) Math.round(Math.random() * 100);
int b = (int) Math.round(Math.random() * 100);
int m;
Random rand = new Random();
m = (int) rand.nextInt(4) + 1;
switch (m) {
case 1:
a = b + (int) Math.round(Math.random() * 100);
while(b == 0){
b = (int) Math.round(Math.random() * 100);
}
while(a % b != 0){
a = (int) Math.round(Math.random() * 100);
}
System.out.println(a + "/" + b + "=");
int c0 = in.nextInt();
out.println(a + "/" + b + "=" + c0);
if (c0 == s.chufa(a, b)) {
sum += 10;
System.out.println("回答正确！");
}
else {
System.out.println("回答错误！");
}
break;
case 2:
System.out.println(a + "*" + b + "=");
int c = in.nextInt();
System.out.println(a + "*" + b + "=" + c);
if (c == s.chengfa(a, b)) {
sum += 10;
System.out.println("回答正确！");
} else {
System.out.println("回答错误！");
}
break;
case 3:
System.out.println(a + "+" + b + "=");
int c1 = in.nextInt();
out.println(a + "+" + b + "=" + c1);
if (c1 == s.jiafa(a, b)) {
sum += 10;
System.out.println("回答正确！");
} else {
System.out.println("回答错误！");
}
break;
case 4:
while (a < b) {
b = (int) Math.round(Math.random() * 100);
}
System.out.println(a + "-" + b + "=");
int c2 = in.nextInt();
out.println(a + "-" + b + "=" + c2);
if (c2 == s.jianfa(a, b)) {
sum += 10;
System.out.println("回答正确！");
} else {
System.out.println("回答错误！");
}
break;
}
}
System.out.println("你的总成绩为" + sum);
out.println("你的总成绩为" + sum);
out.close();
}
public int jiafa(int a,int b) {
return a + b;
}
public int jianfa(int a, int b) {
return a - b;
}
public int chengfa(int a, int b) {
return a * b;
}
public int chufa(int a, int b) {
if (b != 0 && a%b==0)
return a / b;
else
return 0;
}
}
package 计算器;
public class Student<T> {
private T a;
private T b;
public Student() {
a = null;
b = null;
}
public Student(T a, T b) {
this.a = a;
this.b = b;
}
}
在运行她的这个实验时，偶尔会出现只有九道题的情况，不知是么原因
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+"\t"+sex+"\t"+age+"\t"+number+"\t"+province+"\n";
}
}
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。
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();
}
}
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;
}
}
总结：本次实验和同伴一起编程，才发现思想不一样得到问题的解决方式也不太一样，我们不断的找问题，找方法，体验一起编程的过程还不错，
