20175314薛勐 数据结构-排序（选做）

数据结构-排序（选做）

要求

在数据结构和算法中，排序是很重要的操作，要让一个类可以进行排序，有两种方法：

• 有类的源代码，针对某一成员变量排序，让类实现Comparable接口,调用Collection.sort(List)
• 没有类的源代码，或者多种排序，新建一个类，实现Comparator接口 调用Collection.sort(List, Compatator)
  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
3. 课下提交代码到码云

代码

Student.java

class Student{
    private String id;//表示学号
    private String name;//表示姓名
    private int age;//表示年龄
    private char sex;//表示性别
    private double computer_score;//表示计算机课程的成绩
    private double english_score;//表示英语课的成绩
    private double maths_score;//表示数学课的成绩
    private double total_score;// 表示总成绩
    private double ave_score; //表示平均成绩
    public Student(String id, String name){
        this.id = id;
        this.name = name;
    }
    public Student(String id, String name, char sex, int age,
                   double computer_score,double english_score,double maths_score){
        this(id, name);
        this.sex = sex;
        this.age = age;
        this.computer_score=computer_score;
        this.english_score=english_score;
        this.maths_score=maths_score;
    }
    public String getId(){
        return id;
    }//获得当前对象的学号，
    public double getComputer_score(){
        return computer_score;
    }//获得当前对象的计算机课程成绩,
    public double getMaths_score(){
        return maths_score;
    }//获得当前对象的数学课程成绩,
    public double getEnglish_score(){
        return english_score;
    }//获得当前对象的英语课程成绩,

    public void setId(String id){
        this.id=id;
    }// 设置当前对象的id值,
    public void setComputer_score(double computer_score){
        this.computer_score=computer_score;
    }//设置当前对象的Computer_score值,
    public void setEnglish_score(double english_score){
        this.english_score=english_score;
    }//设置当前对象的English_score值,
    public void setMaths_score(double maths_score){
        this.maths_score=maths_score;
    }//设置当前对象的Maths_score值,

    public double getTotalScore(){
        return computer_score+maths_score+english_score;
    }// 计算Computer_score, Maths_score 和English_score 三门课的总成绩。
    public double getAveScore(){
        return getTotalScore()/3;
    }// 计算Computer_score, Maths_score 和English_score 三门课的平均成绩。
    @Override
    public String toString(){
        total_score=getTotalScore();
        return "Student[姓名："+name+"，学号："+id+"，总成绩："+total_score+"]";
    }
}

StudentSortID.java

import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
public class StudentSortID {
    public static void main(String[] args) {
        List<Student> list = new LinkedList<Student>();
        list.add(new Student("20175316", "盛茂淞", 'M',
                20, 89, 92, 76));
        list.add(new Student("20175313", "张黎仙", 'F',
                19, 95, 73, 99));
        list.add(new Student("20175315", "陈煜扬", 'M',
                20, 79, 64, 79));
        list.add(new Student("20175314", "薛勐", 'M',
                19, 90, 75, 80.5));
        list.add(new Student("20175312", "陶光远", 'M',
                20, 83, 85, 90));
        Iterator<Student> iterator = list.iterator();
        System.out.println("排序前：");
        while (iterator.hasNext()) {
            Student stu = iterator.next();
            System.out.println(stu.toString());
        }
        Collections.sort(list, new ComparatorByID());
        System.out.println("按照学号排序后：");
        iterator = list.iterator();
        while (iterator.hasNext()) {
            Student stu = iterator.next();
            System.out.println(stu.toString());
        }
    }
}

StudentSortMark.java

import java.util.Collections;
import java.util.Iterator;
import java.util.LinkedList;
import java.util.List;
public class StudentSortMark {
    public static void main(String[] args) {
        List<Student> list = new LinkedList<Student>();
        list.add(new Student("20175312", "陶光远", 'M',
                20, 83, 85, 90));
        list.add(new Student("20175313", "张黎仙", 'F',
                19, 95, 73, 99));
        list.add(new Student("20175314", "薛勐", 'M',
                19, 90, 75, 80.5));
        list.add(new Student("20175315", "陈煜扬", 'M',
                20, 79, 64, 79));
        list.add(new Student("20175316", "盛茂淞", 'M',
                20, 89, 92, 76));
        Iterator<Student> iterator = list.iterator();
        System.out.println("排序前：");
        while (iterator.hasNext()) {
            Student stu = iterator.next();
            System.out.println(stu.toString());
        }
        Collections.sort(list, new ComparatorByMark());
        System.out.println("按照总分排序后：");
        iterator = list.iterator();
        while (iterator.hasNext()) {
            Student stu = iterator.next();
            System.out.println(stu.toString());
        }
    }
}

ComparatorByID.java

import java.util.Comparator;
import java.util.*;
public class ComparatorByID implements Comparator<Student> {
    @Override
    public int compare(Student o1, Student o2)
    {
        return Integer.parseInt(o1.getId()) - Integer.parseInt(o2.getId());
    }
}

ComparatorByMark.java

import java.util.Comparator;
public class ComparatorByMark implements Comparator<Student> {
    @Override
    public int compare(Student stu1, Student stu2){
        return (int)(stu1.getTotalScore()-stu2.getTotalScore());
    }
}

测试结果

StudentSortID.java

StudentSortMark.java

码云链接

参考资料

Java数据结构与排序