理論學習部分：

JAVA的集合框架

l JAVA的集合框架實現對各種數據結構的封裝，以降低對數據管理與處理的難度。

l 所謂框架就是一個類庫的集合，框架中包含很多超類，編程者創建這些超類的子類可較方便的設計設計程序所需的類。例如：Swing類包

l 集合(Collection或稱為容器)是一種包含多個元素并提供對所包含元素操作方法的類，其包含的元素可以由同一類型的對象組成，也可以由不同類型的對象組成。

l 集合框架：JAVA集合類庫的統一架構。

1.集合類的作用

l 集合類的作用：?

– Java的集合類提供了一些基本數據結構的支持。

– 例如Vector、Hashtable、Stack等。

l 集合類的使用：

– Java的集合類包含在java.util包中。

– import java.util.*;

2.集合類的特點

l 特點一：

– 只容納對象。

注意：數組可以容納基本數據類型數據和對象。

– 如果集合類中想使用基本數據類型，又想利用集合類的靈活性，可以把基本數據類型數據封裝成該數據類型的包裝器對象，然后放入集合中處理。

l 特點二：?

– 集合類容納的對象都是Object類的實例，一旦把一個對象置入集合類中，它的類信息將丟失，這樣設計的目的是為了集合類的通用性。

– 因為Object類是所有類的祖先，所以可以在這些集合中存放任何類的對象而不受限制，但切記在使用集合成員之前必須對它重新造型。

3.?新舊集合類

Vector類

Stack類

Hashtable類

Vector類
? Vector類類似長度可變的數組。
? Vector中只能存放對象。 ? Vector的元素通過下標進行訪問。
? Vector類關鍵屬性： – capacity表示集合最多能容納的元素個數。 – capacityIncrement表示每次增加多少容量。 – size表示集合當前元素個數。
Vector v = new Vector(100)

1、實驗目的與要求

(1) 掌握Vetor、Stack、Hashtable三個類的用途及常用API；

(2) 了解java集合框架體系組成；

(3) 掌握ArrayList、LinkList兩個類的用途及常用API。

(4) 了解HashSet類、TreeSet類的用途及常用API。

(5)了解HashMap、TreeMap兩個類的用途及常用API；

(6)?結對編程（Pair programming）練習，體驗程序開發中的兩人合作。

2、實驗內容和步驟

實驗1：?導入第9章示例程序，測試程序并進行代碼注釋。

測試程序1：

l?使用JDK命令運行編輯、運行以下三個示例程序，結合運行結果理解程序；

掌握Vetor、Stack、Hashtable三個類的用途及常用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();} }

修改為：

package 王志成;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++) {if(cats.elementAt(i) instanceof Cat) {((Cat) cats.elementAt(i)).print();}else {((Dog) cats.elementAt(i)).print();}}} }

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package 王志成; 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());} }

package 王志成;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++;elseht.put(r, new Counter());}System.out.println(ht);} }

測試程序2：

l?使用JDK命令編輯運行ArrayListDemo和LinkedListDemo兩個程序，結合程序運行結果理解程序；

package 王志成; import java.util.*;public class ArrayListDemo {public static void main(String[] argv) {ArrayList<Comparable> 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));}} }

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package 王志成;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");elseSystem.err.println("Lookup works");} }

l?在Elipse環境下編輯運行調試教材360頁程序9-1，結合程序運行結果理解程序；

l?掌握ArrayList、LinkList兩個類的用途及常用API。

package 王志成;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());}System.out.println(a);// remove every second word from b bIter = b.iterator();while (bIter.hasNext()){bIter.next(); // skip one elementif (bIter.hasNext()){bIter.next(); // skip next elementbIter.remove(); // remove that element }}System.out.println(b);// bulk operation: remove all words in b from a a.removeAll(b);System.out.println(a);} }

測試程序3：

l?運行SetDemo程序，結合運行結果理解程序；

package 王志成; 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"); // DUPLICATEh.add("Three");Iterator it = h.iterator();while (it.hasNext()) {System.out.println(it.next());}} }

l?在Elipse環境下調試教材365頁程序9-2，結合運行結果理解程序；了解HashSet類的用途及常用API。

l?在Elipse環境下調試教材367頁-368程序9-3、9-4，結合程序運行結果理解程序；了解TreeSet類的用途及常用API。

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package 王志成;import java.util.*;/*** This program uses a set to print all unique words in System.in.* @version 1.12 2015-06-21* @author Cay Horstmann*/ public class SetTest {public static void main(String[] args){Set<String> words = new HashSet<>(); // HashSet implements Setlong totalTime = 0;try (Scanner in = new Scanner(System.in)){while (in.hasNext()){String word = in.next();long callTime = System.currentTimeMillis();words.add(word);callTime = System.currentTimeMillis() - callTime;totalTime += callTime;}}Iterator<String> iter = words.iterator();for (int i = 1; i <= 20 && iter.hasNext(); i++)System.out.println(iter.next());System.out.println(". . .");System.out.println(words.size() + " distinct words. " + totalTime + " milliseconds.");} }

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l?在Elipse環境下調試教材367頁-368程序9-3、9-4，結合程序運行結果理解程序；了解TreeSet類的用途及常用API。

package 王志成;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));sortByDescription.addAll(parts);System.out.println(sortByDescription);} }

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package 王志成;import java.util.*;/*** An item with a description and a part number.*/ public class Item implements Comparable<Item>//Item類實現Comparable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;//字符串partNumber = aPartNumber;}/*** Gets the description of this item.* * @return the description*/public String getDescription(){return description;}public String toString(){return "[description=" + description + ", partNumber=" + partNumber + "]";}//返回該對象的字符串表示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);} }

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測試程序4：

使用JDK命令運行HashMapDemo程序，結合程序運行結果理解程序；

package 王志成; 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);} }

l?在Elipse環境下調試教材373頁程序9-6，結合程序運行結果理解程序；

l?了解HashMap、TreeMap兩個類的用途及常用API。

?

package 王志成;import java.util.*;/*** This program demonstrates how to extend the collections framework.* @version 1.21 2012-01-26* @author Cay Horstmann*/ public class CircularArrayQueueTest {public static void main(String[] args){Queue<String> q = new CircularArrayQueue<>(5);q.add("Amy");q.add("Bob");q.add("Carl");q.add("Deedee");q.add("Emile");q.remove();q.add("Fifi");q.remove();for (String s : q) System.out.println(s);} }/** A first-in, first-out bounded collection. */ class CircularArrayQueue<E> extends AbstractQueue<E> { private Object[] elements; private int head; private int tail; private int count; private int modcount;/** Constructs an empty queue. @param capacity the maximum capacity of the queue */ public CircularArrayQueue(int capacity) { elements = new Object[capacity]; count = 0; head = 0; tail = 0; } public boolean offer(E newElement) { assert newElement != null;if (count < elements.length) {elements[tail] = newElement; tail = (tail + 1) % elements.length; count++;modcount++;return true;}else return false;} public E poll() { if (count == 0) return null;E r = peek(); head = (head + 1) % elements.length; count--; modcount++;return r; } @SuppressWarnings("unchecked")public E peek() { if (count == 0) return null;return (E) elements[head]; } public int size() { return count; } public Iterator<E> iterator(){return new QueueIterator();}private class QueueIterator implements Iterator<E>{private int offset;private int modcountAtConstruction;public QueueIterator(){modcountAtConstruction = modcount;}@SuppressWarnings("unchecked")public E next() { if (!hasNext()) throw new NoSuchElementException();E r = (E) elements[(head + offset) % elements.length]; offset++;return r;}public boolean hasNext() { if (modcount != modcountAtConstruction) throw new ConcurrentModificationException();return offset < count;}public void remove() { throw new UnsupportedOperationException(); }} }

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實驗2：結對編程練習：

l?關于結對編程：以下圖片是一個結對編程場景：兩位學習伙伴坐在一起，面對著同一臺顯示器，使用著同一鍵盤，同一個鼠標，他們一起思考問題，一起分析問題，一起編寫程序。

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l?關于結對編程的闡述可參見以下鏈接：

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

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

l?對于結對編程中代碼設計規范的要求參考：

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

?

以下實驗，就讓我們來體驗一下結對編程的魅力。

l?確定本次實驗結對編程合作伙伴；

l?各自運行合作伙伴實驗九編程練習1，結合使用體驗對所運行程序提出完善建議；

l?各自運行合作伙伴實驗十編程練習2，結合使用體驗對所運行程序提出完善建議；

合作伙伴：王之泰

合作伙伴的實驗代碼及結果如下：

實驗九：

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 main{private static ArrayList<person> Personlist;public static void main(String[] args) {Personlist = new ArrayList<>();Scanner scanner = new Scanner(System.in);File file = new File("D:\\身份證號.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 ID = linescanner.next();String sex = linescanner.next();String age = linescanner.next();String place =linescanner.nextLine();person Person = new person();Person.setname(name);Person.setID(ID);Person.setsex(sex);int a = Integer.parseInt(age);Person.setage(a);Person.setbirthplace(place);Personlist.add(Person);}} catch (FileNotFoundException e) {System.out.println("查找不到信息");e.printStackTrace();} catch (IOException e) {System.out.println("信息讀取有誤");e.printStackTrace();}boolean isTrue = true;while (isTrue) {System.out.println("1:按姓名字典序輸出人員信息");System.out.println("2:查詢最大年齡與最小年齡人員信息");System.out.println("3：輸入你的年齡，查詢與你最近人的姓名、身份證號、年齡、性別和出生地；");System.out.println("4:查詢是否有同鄉");System.out.println("5：退出");int nextInt = scanner.nextInt();switch (nextInt) {case 1:Collections.sort(Personlist);System.out.println(Personlist.toString());break;case 2:int max=0,min=100;int j,k1 = 0,k2=0;for(int i=1;i<Personlist.size();i++){j=Personlist.get(i).getage();if(j>max){max=j; k1=i;}if(j<min){min=j; k2=i;}} System.out.println("年齡最大："+Personlist.get(k1));System.out.println("年齡最小："+Personlist.get(k2));break;case 3:System.out.println("年齡：");int yourage = scanner.nextInt();int near=agenear(yourage);int d=yourage-Personlist.get(near).getage();System.out.println(""+Personlist.get(near));break;case 4:System.out.println("你的家鄉?");String find = scanner.next(); String place=find.substring(0,3);String place2=find.substring(0,3);for (int i = 0; i <Personlist.size(); i++) {if(Personlist.get(i).getbirthplace().substring(1,4).equals(place)) System.out.println(""+Personlist.get(i));} break;case 5:isTrue = false;System.out.println("退出程序!");break;default:System.out.println("輸入有誤");}}}public static int agenear(int age) {int j=0,min=53,d=0,k=0;for (int i = 0; i < Personlist.size(); i++){d=Personlist.get(i).getage()-age;if(d<0) d=-d; if (d<min) {min=d;k=i;}} return k;}} public class person implements Comparable<person> { private String name; private String ID; private int age; private String sex; 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 int getage() {return age; } public void setage(int age) {// int a = Integer.parseInt(age); this.age= age; } public String getsex() { return sex; } public void setsex(String sex) { this.sex= sex; } public String getbirthplace() { return birthplace; } public void setbirthplace(String birthplace) { this.birthplace= birthplace; }public int compareTo(person o) {return this.name.compareTo(o.getname());}public String toString() {return name+"\t"+sex+"\t"+age+"\t"+ID+"\t"+birthplace+"\n";}}

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?實驗十

import java.io.File;
import java.io.FileOutputStream;
import java.io.PrintWriter;
import java.math.BigDecimal;
import java.util.Scanner;

public class ss {
public static void main(String[] args) {

Scanner in = new Scanner(System.in);
Calculator<Integer> sf = new Calculator<Integer>();
File file = new File("wzt.txt");
if(file.exists()) {
System.out.println("文件已存在");
}
PrintWriter output = null;
try {
output = new PrintWriter(new FileOutputStream(file));
} catch (Exception e) {
//e.printStackTrace();
}
int sum = 0;

System.out.println("計算結果保留兩位小數");
for (int i = 1; i < 11; i++) {
int a = (int) Math.round(Math.random() * 100);
int b = (int) Math.round(Math.random() * 100);
int s = (int) Math.round(Math.random() * 3);

switch(s)
{
case 1:
System.out.println(i+": "+a+"/"+b+"=");
Number c = in.nextDouble();
output.println(a+"/"+b+"="+c);
Number g = sf.division(a, b);
BigDecimal division = new BigDecimal(g.doubleValue());
g = division.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();
if (c.equals(g)) {
sum += 10;
System.out.println("恭喜答案正確");
}
else {
System.out.println("抱歉，答案錯誤");
}

break;

case 2:
System.out.println(i+": "+a+"*"+b+"=");
Number c1 = in.nextDouble();
output.println(a+"*"+b+"="+c1);
Number g1 = sf.mulitiplication(a, b);
BigDecimal mul = new BigDecimal(g1.doubleValue());
g1 = mul.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();
if (c1.equals(g1) ){
sum += 10;
System.out.println("恭喜答案正確");
}
else {
System.out.println("抱歉，答案錯誤");
}
break;
case 3:
System.out.println(i+": "+a+"+"+b+"=");
Number c2 = in.nextDouble();
output.println(a+"+"+b+"="+c2);
Number g2 =sf.addition(a, b);
BigDecimal add = new BigDecimal(g2.doubleValue());
g2 = add.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();
if (c2.equals(g2)) {
sum += 10;
System.out.println("恭喜答案正確");
}
else {
System.out.println("抱歉，答案錯誤");
}

break ;
case 4:
System.out.println(i+": "+a+"-"+b+"=");
Number c3 = in.nextDouble();
output.println(a+"-"+b+"="+c3);
Number g3 = sf.subtraction(a, b);
BigDecimal sub = new BigDecimal(g3.doubleValue());
g3 = sub.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();
if (c3.equals(g3)) {
sum += 10;
System.out.println("恭喜答案正確");
}
else {
System.out.println("抱歉，答案錯誤");
}
break ;

}

}
System.out.println("成績"+sum);
output.println("成績:"+sum);
output.close();
in.close();

}
}

public class Calculator<T> {public Calculator() {// TODO Auto-generated constructor stub }public Number addition(T m,T n) {return Double.parseDouble(m.toString())+Double.parseDouble(n.toString());}public Number subtraction(T m,T n) {return Double.parseDouble(m.toString())-Double.parseDouble(n.toString());}public Number mulitiplication(T m,T n) {return Double.parseDouble(m.toString())*Double.parseDouble(n.toString());}public Number division(T m,T n) {if(Double.parseDouble(n.toString()) != 0)return Double.parseDouble(m.toString())/Double.parseDouble(n.toString());elsereturn 0;} }

完善意見：通過運行他的實驗代碼，可以看出他的代碼寫得很完善，很嚴謹，但或許會有一絲繁瑣，可以適當的簡化，但對現階段的我們來說，這樣或許更好的能幫助我們加深所學知識的理解。

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結對編程代碼如下：

package jiedui_bianchen;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.Scanner; import java.util.Collections;public class ID {public static People findPeopleByname(String name) {People flag = null;for (People people : peoplelist) {if(people.getName().equals(name)) {flag = people;}}return flag;}public static People findPeopleByid(String id) {People flag = null;for (People people : peoplelist) {if(people.getnumber().equals(id)) {flag = people;}}return flag;}private static ArrayList<People> agenear(int yourage) {// TODO Auto-generated method stubint j=0,min=53,d_value=0,k = 0;ArrayList<People> plist = new ArrayList<People>();for (int i = 0; i < peoplelist.size(); i++) {d_value = peoplelist.get(i).getage() > yourage ? peoplelist.get(i).getage() - yourage : yourage - peoplelist.get(i).getage() ;k = d_value < min ? i : k;min = d_value < min ? d_value : min;}for(People people : peoplelist) {if(people.getage() == peoplelist.get(k).getage()) {plist.add(people);}}return plist;}private static ArrayList<People> peoplelist; public static void main(String[] args) //throws IOException {peoplelist = new ArrayList<People>();Scanner scanner = new Scanner(System.in);File file = new File("D:\\身份證號.txt");try {FileInputStream files = new FileInputStream(file);BufferedReader in = new BufferedReader(new InputStreamReader(files));String temp = null;while ((temp = in.readLine()) != null) {String[] information = temp.split("[ ]+");People people = new People();people.setName(information[0]);people.setnumber(information[1]);int A = Integer.parseInt(information[3]);people.setage(A);people.setsex(information[2]);for(int j = 4; j<information.length;j++) {people.setplace(information[j]);}peoplelist.add(people);}} catch (FileNotFoundException e) {System.out.println("文件未找到");e.printStackTrace();} catch (IOException e) {System.out.println("文件讀取錯誤");e.printStackTrace();}boolean isTrue = true;while (isTrue) {System.out.println("******************************************");System.out.println(" 1.按姓名典序輸出人員信息");System.out.println(" 2.查詢最大年齡人員信息");System.out.println(" 3.查詢最小年齡人員信息");System.out.println(" 4.輸入你的年齡，查詢身份證號.txt中年齡與你最近的人");System.out.println(" 5.查詢人員中是否有你的同鄉");System.out.println(" 6.退出");System.out.println("******************************************");int nextInt = scanner.nextInt();switch (nextInt) {case 1:Collections.sort(peoplelist);System.out.println(peoplelist.toString());break;case 2:int max=0;int j,k1 = 0;for(int i=1;i<peoplelist.size();i++){j = peoplelist.get(i).getage();if(j>max){max = j; k1 = i;}} System.out.println("年齡最大："+peoplelist.get(k1));break;case 3:int min = 100;int j1,k2 = 0;for(int i=1;i<peoplelist.size();i++){j1 = peoplelist.get(i).getage();if(j1<min){min = j1; k2 = i;}} System.out.println("年齡最小："+peoplelist.get(k2));break;case 4:System.out.println("年齡：");int input_age = scanner.nextInt();ArrayList<People> plist = new ArrayList<People>();plist = agenear(input_age);for(People people : plist) {System.out.println(people.toString());}break;case 5:System.out.println("請輸入省份");String find = scanner.next(); for (int i = 0; i <peoplelist.size(); i++) {String [] place = peoplelist.get(i).getplace().split("\t");for(String temp : place) {if(find.equals(temp)) {System.out.println("你的同鄉是 "+peoplelist.get(i));break;}}} break;case 6:isTrue = false;System.out.println("byebye!");break;default:System.out.println("輸入有誤");}}}}

結對程序運行功能界面截圖；

結對過程描述，提供兩人在討論、細化和編程時的結對照片(非擺拍)。

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5.采用結對編程方式，與學習伙伴合作完成實驗十編程練習2。

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import java.io.File; import java.io.FileOutputStream; import java.io.PrintWriter; import java.math.BigDecimal; import java.util.Scanner;public class ss {public static void main(String[] args) {Scanner in = new Scanner(System.in);Calculator<Integer> sf = new Calculator<Integer>();File file = new File("wzt.txt");if(file.exists()) {System.out.println("文件已存在");}PrintWriter output = null;try {output = new PrintWriter(new FileOutputStream(file));} catch (Exception e) {//e.printStackTrace(); }int sum = 0;System.out.println("計算結果保留兩位小數");for (int i = 1; i < 11; i++) {int a = (int) Math.round(Math.random() * 100);int b = (int) Math.round(Math.random() * 100);int s = (int) Math.round(Math.random() * 3);switch(s){case 1:System.out.println(i+": "+a+"/"+b+"=");Number c = in.nextDouble();output.println(a+"/"+b+"="+c);Number g = sf.division(a, b);BigDecimal division = new BigDecimal(g.doubleValue());g = division.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();if (c.equals(g)) {sum += 10;System.out.println("恭喜答案正確");}else {System.out.println("抱歉，答案錯誤");}break;case 2:System.out.println(i+": "+a+"*"+b+"=");Number c1 = in.nextDouble();output.println(a+"*"+b+"="+c1);Number g1 = sf.mulitiplication(a, b);BigDecimal mul = new BigDecimal(g1.doubleValue());g1 = mul.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();if (c1.equals(g1) ){sum += 10;System.out.println("恭喜答案正確");}else {System.out.println("抱歉，答案錯誤");}break;case 3:System.out.println(i+": "+a+"+"+b+"=");Number c2 = in.nextDouble();output.println(a+"+"+b+"="+c2);Number g2 =sf.addition(a, b);BigDecimal add = new BigDecimal(g2.doubleValue());g2 = add.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();if (c2.equals(g2)) {sum += 10;System.out.println("恭喜答案正確");}else {System.out.println("抱歉，答案錯誤");}break ;case 4:System.out.println(i+": "+a+"-"+b+"=");Number c3 = in.nextDouble();output.println(a+"-"+b+"="+c3);Number g3 = sf.subtraction(a, b);BigDecimal sub = new BigDecimal(g3.doubleValue());g3 = sub.setScale(2, BigDecimal.ROUND_HALF_UP).doubleValue();if (c3.equals(g3)) {sum += 10;System.out.println("恭喜答案正確");}else {System.out.println("抱歉，答案錯誤");}break ;} }System.out.println("成績"+sum);output.println("成績:"+sum);output.close();in.close();} }

結對程序運行功能界面截圖；

結對過程描述，提供兩人在討論、細化和編程時的結對照片(非擺拍)。

?總結 ：通過這周的Java課程的學習，基本掌握了java中集合的概念，學習了集合的知識以及使用方法。實驗中，運用了結對編程的方法，? 通過結對編程，極大的提高了我們的編程興趣，和編程效率，是一種很好的編程方式。

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轉載于:https://www.cnblogs.com/847118824wang/p/9941802.html

總結

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