Question

我试图按照递增顺序对ArrayList进行排序以引用某个变量。这是一个问题。

q5：创建一个名为Snow的公共类，其私有实例变量vast，prior，ethnic和remarkable各有{{1}类型}。您可以在此课程中添加您想要的任何其他方法和变量。

在int之外（在问题集类中）编写一个名为Snow的公共静态方法，该方法将sortSnow个Snows作为参数并返回void。此方法将按变量ArrayList按递增顺序对输入进行排序

这就是我写的。

remarkable

我不明白错误的含义。 autolab给了我这个错误：

无法找到课程public class snow implements Comparable<snow> { private int vast; private int prior; private int ethnic; private int remarkable; public snow( int vast , int prior, int ethnic ,int remarkable) { this.vast=vast; this.prior = prior; this.ethnic = ethnic; this.remarkable = remarkable; } public int getEthnic() { return ethnic; } public void setEthnic(int ethnic) { this.ethnic = ethnic; } public int getPrior() { return prior; } public void setPrior(int prior) { this.prior = prior; } public int getVast() { return vast; } public void setVast(int vast) { this.vast = vast; } public int getRemarkable() { return remarkable; } public void setRemarkable(int remarkable) { this.remarkable = remarkable; } public int compareTo(snow compareSnow) { // TODO Auto-generated method stub int compareThese = ((snow) compareSnow).getRemarkable(); //ascending order return this.remarkable - compareThese; } } public static void sortSnow(ArrayList<snow>input){ Collections.sort(input); }

Answer 1

Java区分大小写，即雪不是雪不是。将您的班级重命名为Snow，然后重试。此外，它是ArrayList而不是arraylist。

然后，要对列表进行排序，您可以使用public static TimeSpan ParseDuration(string input) { string[] inputParts = input.Split(':'); string ddString = inputParts[0]; string hhString = inputParts[1]; string mmString = inputParts[2]; string ssString = inputParts[3]; int dd = int.Parse(ddString, CultureInfo.InvariantCulture); int hh = int.Parse(hhString, CultureInfo.InvariantCulture); int mm = int.Parse(mmString, CultureInfo.InvariantCulture); int ss = int.Parse(ssString, CultureInfo.InvariantCulture); return new TimeSpan(dd, hh, mm, ss); }。

Answer 2

我认为这是你要实现的目标

将以下代码保存在名为＆＃34; Snow.java＆＃34;的文件中。编译它并尝试运行它。

import java.util.ArrayList;
import java.util.Collections;

//As ".java" file can contain only single public java class
//I made Problem set class non-public so we can use its main method
//to run and see output

class ProblemSet {

public static void main(String[] args) {

    Snow one = new Snow(1,1,1,1);
    Snow two = new Snow(1,1,1,2);
    Snow three = new Snow(1,1,1,3);
    Snow four = new Snow(1,1,1,4);
    Snow five = new Snow(1,1,1,5);
    Snow six = new Snow(1,1,1,6);

    ArrayList arrayList = new ArrayList();
    arrayList.add(one);
    arrayList.add(three);
    arrayList.add(five);
    arrayList.add(two);
    arrayList.add(six);
    arrayList.add(four);

    System.out.println("Without sort");
    System.out.println(arrayList);

    sortSnow(arrayList);

    System.out.println("With sort");
    System.out.println(arrayList);

}

//this is your static method which takes argument as array list of Snow
//And it applies sorting logic based on compareTo method which you wrote
//in Snow class. As per java best practice Class name should start with 
//Upper case letters and follow camel casing I renamed your class from 
//"snow" to "Snow"
public static void sortSnow(ArrayList<Snow> input){
    Collections.sort(input);
}

}

//This is you public class Snow
//If you want to keep it in separate java file put it

public class Snow implements Comparable<Snow> {
private int vast;
private int prior;
private int ethnic;
private int remarkable;

public Snow(int vast, int prior, int ethnic, int remarkable) {
    this.vast = vast;
    this.prior = prior;
    this.ethnic = ethnic;
    this.remarkable = remarkable;
}

public int getEthnic() {
    return ethnic;
}

public void setEthnic(int ethnic) {
    this.ethnic = ethnic;
}

public int getPrior() {
    return prior;
}

public void setPrior(int prior) {
    this.prior = prior;
}

public int getVast() {
    return vast;
}

public void setVast(int vast) {
    this.vast = vast;
}

public int getRemarkable() {
    return remarkable;
}

public void setRemarkable(int remarkable) {
    this.remarkable = remarkable;
}

public int compareTo(Snow compareSnow) {
    // TODO Auto-generated method stub


    int compareThese = ((Snow) compareSnow).getRemarkable();

    //ascending order
    return this.remarkable - compareThese;

}

//This is added because when you use array list to print
//it will print remarkable of particular Snow object
@Override
public String toString() {
    return String.valueOf(remarkable);
}
}

在Autolab分配中找不到类错误

2 个答案: