java - 尝试按字母顺序对我的电影标题进行排序，然后将它们与我的评级数组中的评级之一一起显示

Question

我尝试对代码进行排序并交换不按字母顺序排列的标题，然后显示结果，但没有成功。没有错误，但由于数组未使用，因此不会显示电影标题。不知道我做错了什么。我尝试过谷歌搜索，但就我而言，我不知道我错过了什么。

主要

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package movieapp;

/**
 *
 * @author T
 */
import java.util.*;
public class Movieapp {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
        moviearray arrMovie;
        arrMovie = new moviearray(5);
        int nElems = 5;

        String movieArr[] = {"Lion king", "Avengers", "Interstellar", "Batman", "13 Hours"};
        int ratingArr[] = {4, 5, 8, 10, 3};

    arrMovie.sort();
    arrMovie.display();
    }


}

电影课

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package movieapp;

/**
 *
 * @author T
 */
public class movie {

    String movie;
    int rating;

    movie(String m, int r){
        this.movie = m;
        this.rating = r;


    }

    public void info(){
        System.out.println("The movie " + this.movie + " is rated a " + this.rating);
    }

}

电影数组类

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package movieapp;

/**
 *
 * @author T
 */
public class moviearray {

    private movie[] arrMovie;
    private int nElems = 0;

    moviearray(int size) {
        arrMovie = new movie[size];
        nElems = 0;
    }

    public void sort() {
        int out;
        int in;
        for (out = nElems - 1; out > 1; out--) {
            for (in = 0; in < out; in++) {
                if (arrMovie[in].movie.compareToIgnoreCase(arrMovie[in + 1].movie) > 0) {
                    swap(in, in + 1);
                }
            }
        }

    }

    public void swap(int x, int y) {
        movie temp = arrMovie[x];
        arrMovie[x] = arrMovie[y];
        arrMovie[y] = temp;
    }

    public void display() {
        for (int i = 0; i < nElems; i++) {
            arrMovie[i].info();
        }
    }
}

编辑Movieapp Class和Moviearray，添加一组并获取

电影应用

 */
package movieapp;

/**
 *
 * @author T
 */
import java.util.*;
public class Movieapp {

    /**
     * @param args the command line arguments
     */
    public static void main(String[] args) {
        // TODO code application logic here
        moviearray arrMovie;
        arrMovie = new moviearray(5);
        int nElems = 5;

        String movieArr[] = {"Lion king", "Avengers", "Interstellar", "Batman", "13 Hours"};
        int ratingArr[] = {4, 5, 8, 10, 3};

        for(int i = 0; i < nElems; i++){
            arrMovie.setElement(i, movieArr[i], ratingArr[i]);
        }

        for(int i = 0; i < nElems; i++){
            arrMovie.getElement(i).info();
        }
    }


}

电影数组

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package movieapp;

/**
 *
 * @author T
 */
public class moviearray {

    public movie[] arrMovie;
    public int nElems = 0;

    moviearray(int size) {
        arrMovie = new movie[size];
        nElems = 0;
    }


    public void setElement(int index, String movie, int rating){
        arrMovie[index]= new movie(movie, rating);
    }

    public movie getElement(int index){
        return arrMovie[index];
    }

    public void sort() {
        int out;
        int in;
        for (out = nElems - 1; out > 1; out--) {
            for (in = 0; in < out; in++) {
                if (arrMovie[in].movie.compareToIgnoreCase(arrMovie[in + 1].movie) > 0) {
                    swap(in, in + 1);
                }
            }
        }

    }

    public void swap(int x, int y) {
        movie temp = arrMovie[x];
        arrMovie[x] = arrMovie[y];
        arrMovie[y] = temp;
    }

    public void display() {
        for (int i = 0; i < nElems; i++) {
            arrMovie[i].info();
        }
    }
}

输出:

output

现在只需要按字母顺序排列即可。

Answer 1

你做错了。你创建了你的对象，但你没有给这个对象分配值。

moviearray arrMovie;
arrMovie = new moviearray(5);
arrMovie.nElems = 5;
arrMovie.arrMovie = {
   new Movie("Lion king",4), 
   new Movie("Avengers",5),
   new Movie("Interstellar",8),
   new Movie("Batman",10),
   new Movie("13 hours",3)
};

您必须将 nElems 和 arrMovie 更改为公共(public)或为这些字段添加 setter 。

我认为你的设计很糟糕，但这个改变解决了你的问题