20165326第十周课上测试补做
知识点总结
实验主要涉及了链表和泛型的知识点
泛型
使用
class 类名<>声明一个类，要用具体的类型替换泛型链表
- 有若干个节点对象组成的数据结构
- 使用
iterator（）方法获取对象 树集
TreeSet<>,使用.add（）为树集添加节点课上代码
1
针对下面的Student类，使用Comparator编程完成以下功能：
1、在测试类StudentTest中新建学生列表，包括自己和学号前后各两名学生，共5名学生,给出运行结果（排序前，排序后）
2、对这5名同学分别用学号和总成绩进行增序排序，提交两个Comparator的代码
Student类老师已经给出，直接将下面的两个Comparator代码加入即可
代码
import java.util.*;
public class IDComparator implements Comparator {@Overridepublic int compare(Object o1, Object o2) {Student st1 = (Student)o1;Student st2 = (Student)o2;return (Integer.parseInt(st1.getId())-Integer.parseInt(st2.getId()));}
}
---
import java.util.*;
public class scoreComparator implements Comparator {
@Override
public int compare(Object o1, Object o2) {
Student st1 = (Student)o1;
Student st2 = (Student)o2;
return (int) (st1.getTotalScore()-st2.getTotalScore());
}
}运行截图
2
代码
import java.util.*;
public class MyList {public static void main(String [] args) {List<String> list=new LinkedList<String>();list.add("20165325,dj");list.add("20165324,cj");list.add("20165327,jt");list.add("20165328,jw");System.out.println("打印初始链表");
//把上面四个节点连成一个没有头结点的单链表Iterator<String> iter=list.iterator();while(iter.hasNext()){String te=iter.next();System.out.println(te);}
//遍历单链表，打印每个结点的list.add("20165326,cz");
//把你自己插入到合适的位置（学号升序）System.out.println("插入我的学号后排序，打印链表");Collections.sort(list);iter=list.iterator();while(iter.hasNext()){String te=iter.next();System.out.println(te);}
//遍历单链表，打印每个结点的list.remove("20165326,cz");
//从链表中删除自己System.out.println("删除我的学号后打印链表");iter=list.iterator();while(iter.hasNext()){String te=iter.next();System.out.println(te);}
//遍历单链表，打印每个结点的}
}运行截图
ch15课后习题
(1)使用堆栈结构输出an的若干项，其中a_n=2a_n-1+2a_n=2a_(n-1)+2a_(n-2)，a_1=3，a_2=8
import java.util.*;
public class E1 {public static void main(String[] args) {Stack<Integer> stack = new Stack<Integer>();stack.push(new Integer(3));stack.push(new Integer(8));int k = 1;while(k<=10){for(int i=1;i<=2;i++){Integer F1 = stack.pop();int f1 = F1.intValue();Integer F2 = stack.pop();int f2 = F2.intValue();Integer temp = new Integer(2*f1+2*f2);System.out.println(""+temp.toString());stack.push(F2);k++;}}}
}
(2)编写一个程序，将链表中的学生英语成绩单存放到一个树集中，使得按成绩自动排序，并输出排序结果.
import java.util.*;class Student2 implements Comparable{int english = 0;String name;Student2(int english,String name){this.name = name;this.english = english;}@Overridepublic int compareTo(Object b){Student2 st = (Student2)b;return (this.english-st.english);}
}
public class E2 {public static void main(String[] args) {List<Student2> list = new LinkedList<Student2>();int score[] = {98,100,99,96,95,94};String name [] = {"Re","Or","Ye","Gr","Bl","Pu"};for(int i=0;i<score.length;i++){list.add(new Student2(score[i],name[i]));}Iterator<Student2> iter = list.iterator();TreeSet<Student2> mytree = new TreeSet<Student2>();while(iter.hasNext()){Student2 stu = iter.next();mytree.add(stu);}Iterator<Student2> te = mytree.iterator();while (te.hasNext()){Student2 stu = te.next();System.out.println(""+stu.name+" "+stu.english);}}
}
运行结果
(3)有10个U盘，有两个重要属性：价格和容量。编写一个应用程序，使用TreeMap<K,V>类，分别按照价格和容量排序输出10个U盘的详细信息。
import java.util.*;
class UDiscKey implements Comparable{double key = 0;UDiscKey(double d){key = d;}public int compareTo(Object b){UDiscKey disc = (UDiscKey)b;if((this.key-disc.key)==0)return -1;elsereturn (int)((this.key-disc.key)*1000);}
}
class UDisc{int amount;double price;UDisc(int m,double e){amount = m;price = e;}
}
public class E3 {public static void main(String[] args) {TreeMap<UDiscKey,UDisc> treeMap = new TreeMap<UDiscKey,UDisc>();int amount[] = {1,2,3,4,8,16,32,64,128,10};double price[] = {10,20,30,40,70,60,70,100,90,80};UDisc UDisc[] = new UDisc[10];for(int i=0;i<UDisc.length;i++){UDisc[i]= new UDisc(amount[i],price[i]);}System.out.println("按容量排序如下：");UDiscKey key[]= new UDiscKey[10];for(int i=0;i<key.length;i++){key[i] = new UDiscKey(UDisc[i].amount);}for(int i=0;i<UDisc.length;i++){treeMap.put(key[i],UDisc[i]);}int number = treeMap.size();Collection<UDisc> collection = treeMap.values();Iterator<UDisc> iter = collection.iterator();while(iter.hasNext()){UDisc disc = iter.next();System.out.println(""+disc.amount+"G "+disc.price+"元");}treeMap.clear();System.out.println("按价格排序如下：");for(int i=0;i<key.length;i++){key[i] = new UDiscKey(UDisc[i].price);}for(int i=0;i<UDisc.length;i++){treeMap.put(key[i],UDisc[i]);}number = treeMap.size();collection = treeMap.values();iter = collection.iterator();while (iter.hasNext()){UDisc disc = iter.next();System.out.println(""+disc.amount+"G "+disc.price+"元");}}
}运行结果