20165331 2017-2018-2 第十周课下补做
课上内容补做
一、代码检测部分课上已完成
二、排序
截图
代码
import java.util.*;
public class Example {
public static void main(String[] args) {
List<Student> list = new LinkedList<>();
list.add(new Student(20165329,"hjw",89,81,99));
list.add(new Student(20165330,"zyx",86,86,85));
list.add(new Student(20165331,"hl",88,91,86));
list.add(new Student(20165332,"yyz",98,75,77));
list.add(new Student(20165333,"cgc",92,90,96));
SortTotal_score sortBytotal_score = new SortTotal_score();
Collections.sort(list, sortBytotal_score);
SortID sortByID = new SortID();
Collections.sort(list, sortByID);
System.out.println("order 1:");
for (Student student : list) {
System.out.println(student);
}
Collections.sort(list, sortBytotal_score);
System.out.println("goal order:");
for (Student student : list) {
System.out.println(student);
}
}
}
class Student {
private int id;
private String name;
private int age;
private String sex;
private double computer_score;
private double english_score;
private double maths_score;
private double total_score;
private double ave_score;
@Override
public String toString() {
return " "+name+" "+id+" "+total_score;
}
public Student(int id, String name,double computer_score,
double english_score,double maths_score) {
this.id = id;
this.name = name;
this.computer_score = computer_score;
this.english_score = english_score;
this.maths_score = maths_score;
}
public int getId() {
return id;
}
public double getComputer_score() {
return computer_score;
}
public double getMaths_score() {
return maths_score;
}
public double getEnglish_score() {
return english_score;
}
public void setId(int id) {
this.id = id;
}
public void setComputer_score(double computer_score) {
this.computer_score = computer_score;
}
public void setEnglish_score(double english_score) {
this.english_score = english_score;
}
public void setMaths_score(double maths_score) {
this.maths_score = maths_score;
}
public double getTotalScore() {
total_score=computer_score + maths_score + english_score;
return total_score;
}
public double getAveScore() {
return getTotalScore() / 3;
}
}
class SortID implements Comparator<Student> {
@Override
public int compare(Student a, Student b) {
return a.getId() - b.getId();
}
}
class SortTotal_score implements Comparator<Student> {
@Override
public int compare(Student a, Student b) {
return (int)( a.getTotalScore() - b.getTotalScore());
}
}
三、单链表
截图
代码
import java.util.*;
public class List {
public static void main(String [] args) {
Node<String> node1 =new Node<String>("20165329",null);
Node<String> node2 =new Node<String>("20165330",null);
Node<String> node3 =new Node<String>("20165332",null);
Node<String> node4 =new Node<String>("20165333",null);
node1.next=node2;
node2.next=node3;
node3.next=node4;
node4.next=node1;
Node<String> node =node1 ;
System.out.println("before");
for (int i=0;i<4;i++) {
System.out.println(node.data.toString());
node = node.next;
}
System.out.println("after");
node=node1;
Node<String> s=new Node<String>("20165331",null);
for(int i=0;i<5;i++){
System.out.println(node.data.toString());
node = node.next;
if(node==node2){
node2.next=s;
s.next=node3;
}
}
node=node1;
for(int i=0;i<4;i++){
node = node.next;
if(node==s){
s=null;
node2.next=node3;
node3.next=node4;
}
}
node =node1 ;
System.out.println("after delete");
for (int i=0;i<4;i++) {
System.out.println(node.data.toString());
node = node.next;
}
}
}
class Node<String>
{
public String data;
public Node<String> next;
public Node(String data, Node<String> next)
{
this.data = data;
this.next = next;
}
public Node()
{
this(null, null);
}
@Override
public java.lang.String toString()
{
return this.data.toString();
}
}
教材代码分析
15——1
class Cone<E> {
double height;
E bottom; //用泛型类E声明对象bottom
public Cone (E b) {
bottom=b; //给泛型类对象赋值
}
public void setHeight(double h) {
height=h;
}
public double computerVolume() {
String s=bottom.toString();//泛型变量只能调用从Object类继承的或重写的方法
double area=Double.parseDouble(s);
return 1.0/3.0*area*height;
}
}
class Rect {
double sideA,sideB,area;
Rect(double a,double b) {
sideA=a;
sideB=b;
}
public String toString() {
area=sideA*sideB;
return ""+area;
}
}
class Circle {
double area,radius;
Circle(double r) {
radius=r;
}
public String toString() { //重写Object类的toString()方法
area=radius*radius*Math.PI;
return ""+area;
}
}
public class Example15_1 {
public static void main(String args[]) {
Circle circle=new Circle(10);
Cone<Circle> coneOne=new Cone<Circle>(circle);//创建一个（圆）锥对象
coneOne.setHeight(16);
System.out.println(coneOne.computerVolume());
Rect rect=new Rect(15,23);
Cone<Rect> coneTwo=new Cone<Rect>(rect);//创建一个（方）锥对象
coneTwo.setHeight(98);
System.out.println(coneTwo.computerVolume());
}
}
15——2
import java.util.*;
public class Example15_2 {
public static void main(String args[]){
List<String> list=new LinkedList<String>();
//定义一个空链表
for(int i=0;i<=60096;i++){
list.add("speed"+i);
}
Iterator<String> iter=list.iterator(); //获取链表中的迭代器
long starttime=System.currentTimeMillis();
while(iter.hasNext()){
String te=iter.next();
}
//进行遍历
long endTime=System.currentTimeMillis();
long result=endTime-starttime;
System.out.println("使用迭代器遍历集合所用时间:"+result+"毫秒");
starttime=System.currentTimeMillis();
for(int i=0;i<list.size();i++){
String te=list.get(i);
}
endTime=System.currentTimeMillis();
result=endTime-starttime;
System.out.println("使用get方法遍历集合所用时间:"+result+"毫秒");
}
}
15——3
import java.util.*;
public class Example15_3 {
public static void main(String args[]){
LinkedList mylist=new LinkedList();//定义一个空链表
mylist.add("你"); //链表中的第一个节点
mylist.add("好"); //链表中的第二个节点
int number=mylist.size(); //获取链表的长度
for(int i=0;i<number;i++){
String temp=(String)mylist.get(i); //必须强制转换取出的数据
System.out.println("第"+i+"节点中的数据:"+temp);
}
Iterator iter=mylist.iterator();
while(iter.hasNext()) {
String te=(String)iter.next(); //必须强制转换取出的数据
System.out.println(te);
}
}
}
15——4
import java.util.*;
class Student implements Comparable {
int height=0;
String name;
Student(String n,int h) {
name=n;
height = h;
}
public int compareTo(Object b) { // 两个Student对象相等当且仅当二者的height值相等
Student st=(Student)b;
return (this.height-st.height);
}
}
public class Example15_4 {
public static void main(String args[ ]) {
List<Student> list = new LinkedList<Student>();
//定义一个空链表
list.add(new Student("张三",188));
list.add(new Student("李四",178));
list.add(new Student("周五",198));
//向链表中依次添加元素
Iterator<Student> iter=list.iterator();
System.out.println("排序前,链表中的数据");
while(iter.hasNext()){
Student stu=iter.next();
System.out.println(stu.name+ "身高:"+stu.height);
}
//对链表进行遍历
Collections.sort(list);
//进行升序排序
System.out.println("排序后,链表中的数据");
iter=list.iterator();
while(iter.hasNext()){
Student stu=iter.next();
System.out.println(stu.name+ "身高:"+stu.height);
}
Student zhaoLin = new Student("zhao xiao lin",178);
int index = Collections.binarySearch(list,zhaoLin,null);
if(index>=0) {
System.out.println(zhaoLin.name+"和链表中"+list.get(index).name+"身高相同");
}
}
}
15——5
import java.util.*;
public class Example15_5 {
public static void main(String args[ ]) {
List<Integer> list = new LinkedList<Integer>();
//定义一个空链表
for(int i=10;i<=50;i=i+10)
list.add(new Integer(i));
System.out.println("洗牌前,链表中的数据");
Iterator<Integer> iter=list.iterator();
while(iter.hasNext()){
Integer n=iter.next();
System.out.printf("%d ",n.intValue());
}
//遍历链表
Collections.shuffle(list);
//按洗牌算法重新随机排列
System.out.printf("
洗牌后,链表中的数据
");
iter=list.iterator();
while(iter.hasNext()){
Integer n=iter.next();
System.out.printf("%d ",n.intValue());
}
System.out.printf("
再向右旋转1次后,链表中的数据
");
Collections.rotate(list,1);
//旋转链表中的数据
iter=list.iterator();
while(iter.hasNext()){
Integer n=iter.next();
System.out.printf("%d ",n.intValue());
}
}
}
15——6
import java.util.*;
public class Example15_6 {
public static void main(String args[]) {
Stack<Integer> stack=new Stack<Integer>();
//定义一个堆栈对象
stack.push(new Integer(1));
stack.push(new Integer(1));
//进行压栈
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(f1+f2);
System.out.println(""+temp.toString());
stack.push(temp);
stack.push(F2);
k++;
}
}
}
}