我仍然是一个非常新手的程序员，所以请尽量描述。我在让我的所有代码都为我的作业工作时遇到了问题。该作业为我提供了四个不需要更改的完整文件（StudentIf.java，StudentCollectionIf.java，StudentLLNode.java和StudentRecords.java）以及一个带有ID和五个等级的名称列表的测试文本文件。
指派分配说明：https://www.cs.colostate.edu/~cs161/Fall14/more_assignments/P5/P5.html
我修改过的两个文件是Student.java和StudentLL.java。同样在我的运行配置 - 参数中，我有＆＃34; cs161 5＆＃34;。我知道很多，但任何帮助都会很棒。
我知道insort方法根本不是真正干净的代码，但我无法解决任何问题。
我目前正在获得正确的输出，但它们没有排序。
Top Score: 0.0
Avg Score: 0.0
Course: cs161
Adam 2143 85 95 85 75 65 score: 81.00
John 1243 60 70 80 55 55 score: 64.00
Mick 1324 70 60 70 80 90 score: 74.00
Ellen 2341 90 95 88 77 66 score: 83.20
Jim 1234 50 40 50 60 70 score: 54.00
Lena 1423 99 50 90 90 85 score: 82.80
Leila 1432 60 70 60 70 60 score: 64.00
Mike 1342 60 70 80 90 99 score: 79.80
Ada 2134 90 90 90 90 90 score: 90.00
Helen 2314 89 79 99 89 88 score: 88.80
代码：
import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.TreeMap;
public class StudentLL implements StudentCollectionIF{
private String course;
private StudentLLNode head;
private int size;
private boolean debug; // you can set debug in main
// the client code provides the course name
public StudentLL(String course){
this.course = course;
}
public String toString(){
String res = "Course: " + course + "\n";
for(StudentLLNode curr = head; curr !=null; curr=curr.getNext()){
StudentIF nS = curr.getStd();
res = res + nS + "\n";
}
return res;
}
@Override
public boolean insort(StudentIF s) {
StudentLLNode curr = head;
if (s == null) {
return false;
}
if (head == null) {
StudentLLNode student = new StudentLLNode(s);
head = student;
size++;
//System.out.println("working");
return true;
} else {
if (curr.getStd().compareTo(s) == 0) {
return false;
}
Map<Integer, StudentLLNode> tcur = new TreeMap<Integer, StudentLLNode>();
tcur.put(curr.getStd().getId(), curr);
while (curr.getNext() != null) {
curr = curr.getNext();
if(curr.getStd().compareTo(s) == 0) {
return false;
}
tcur.put(curr.getStd().getId(), curr);
}
curr.setNext(new StudentLLNode(s));
tcur.put(curr.getStd().getId(), curr.getNext());
System.out.println(s.getName() + " " + s.getId());
ArrayList<StudentLLNode> bs = new ArrayList<StudentLLNode>();
Iterator it = tcur.entrySet().iterator();
while(it.hasNext()) {
Map.Entry pairs = (Map.Entry)it.next();
StudentLLNode sss = (StudentLLNode) pairs.getValue();
bs.add(sss);
it.remove();
}
for(int i = 0; i < bs.size(); i++) {
//bs.get(i).setNext(bs.get(i + 1));
if(i == bs.size() - 1) {
//bs.get(i).setNext(null);
} else {
//bs.get(i).setNext(bs.get(i + 1));
}
System.out.println("\t" + bs.get(i).toString() + " NET " + bs.get(i).getNext() );
}
//bs.get(bs.size() - 1).setNext(null);
//confused here
/*StudentLLNode student1 = new StudentLLNode(s);
curr.setNext(student1);*/
size++;
return true;
}
}
@Override
public boolean remove(StudentIF s) {
StudentLLNode current = head;
if(s == null){
return false;
}
if(s.equals(current.getStd())){
//StudentLLNode top = head;
head = head.getNext();
size--;
return true;
}
else{
StudentLLNode previous, next;
previous = current;
current = current.getNext();
while(current != null){
next = current.getNext();
if(s.getId() == (current.getStd().getId())){
previous.setNext(next);
size--;
return true;
}
previous = current;
current = next;
}
}
return false;
}
@Override
public int size() {
// TODO Auto-generated method stub
return size;
}
@Override
public double classAvg() {
// int count = 0, total = 0;
// for (int i = 1; i < 5; i++)
// {
// total += computeScore((StudentLLNode) head);
// count++;
// }
// gettop();
// return total / count;
return 0;
}
@Override
public double classTopScore() {
return 0;
}
}
======
import java.text.DecimalFormat;
import java.util.Arrays;
public class Student implements StudentIF{
private String name;
private int id;
private int[] grades;
private int numGrades;
private int totalGrades;
// The constructor
// initializes the instance variables
// name, id, grades = new int[totalGrades], and numGrades = 0;
public Student (String name, int id, int totalGrades){
this.name = name;
this.id = id;
grades = new int[totalGrades];
this.totalGrades = totalGrades;
numGrades= 0;
//System.out.println(name+" "+id+" "+grades[0]+" "+grades[1]+" "+grades[2]+" "+grades[3]+" "+grades[4]+" "+" "+totalGrades);
}
public String toString() {
String res = name + "\t" + id + " ";
for (int i=0; i < totalGrades; i++) {
res += " " + grades[i];
}
res += "\tscore: " + new DecimalFormat("0.00").format(computeScore());
return res;
}
@Override
public int compareTo(StudentIF arg0) {
if (arg0 == null || arg0.getId() != id) {
return 1;
}
/*if (this.id > arg0.getId())
return 1;
else if (this.id < arg0.getId())
return -1;*/
/*else {
return 0;
}*/
return 0;
}
@Override
public String getName() {
return this.name;
}
@Override
public int getId() {
return id;
}
@Override
public double computeScore() {
double total = 0;
if (numGrades == 0) {
return total;
}
if (numGrades > grades.length) {
numGrades = grades.length;
}
for (int i = 0; i < numGrades; i++) {
total += grades[i];
}
return total / grades.length;
}
@Override
public boolean addGrade(int newGrade) {
if(numGrades<grades.length){
grades[numGrades] = newGrade;
numGrades++;
return true;
}
return false;
}
@Override
public boolean equals(StudentIF other) {
if (other == null) {
return false;
}
if (this.id == other.getId()) {
return true;
}
return false;
}
}
答案 0 :(得分：0)
让您的Student类实现Comparable接口并覆盖compareTo方法
Class Student implements Comparable<Student>
{
private int id;
@Override
public int compareTo(Student s) {
if (this.id > s.id)
return 1;
else if (this.id < s.id)
return -1;
else
return 0;
}
}
然后，使用Collections.sort(yourlisthere)，您将获得根据学生id
答案 1 :(得分：0)
为了扩展@Abishek的回答（因为我没有足够的回复评论），compareTo方法可以简化为
public int compareTo(Student s) {
return this.id - s.id;
}
您不需要特别返回1，-1或0，因为您可能会从该答案中推断出来。如果this.id比s.id“更大”，则为正数，反之则为负数，如果它们相等则为0。