如何创建一个数组，以升序组织 taco 价格及其 taco 名称？

Question

这是我到目前为止的代码。我使用字符串方法来表示 taco 名称并使用 double 来表示价格。但是，我不知道如何启动一系列 taco 名称和价格。我需要该数组来生成如下所示的输出：

Sorted Tacos are
Taco Prices Crispy Potato Soft Taco 0.99
Taco Prices Crunchy Taco 1.19
Taco Prices Soft Taco 1.19
Taco Prices Doritos Locos Taco (Nacho Cheese) 1.49
Taco Prices Crunchy Taco Supreme 1.59
Taco Prices Soft Taco Supreme 1.59
Taco Prices Chicken Soft Taco 1.79
Taco Prices Double Decker Taco 1.89
Taco Prices Doritos Locs Tacos(Fiery) Supreme 1.89
Taco Prices Double Decker Taco Supreme 2.29

请有人帮忙。

import java.util.Scanner;
public class TacoSortProgram {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        //Write a program that sorts prices of 10 tacos in ascending order based on the price, using arrays

        System.out.println ("Welcome to the taco price sorter! Enter 10 taco names and prices and I'll sort it!");
        Scanner keyboard = new Scanner(System.in);

           //       System.out.printf("$%4.2f for each %s ", price, item);
           //       System.out.printf("\nThe total is: $%4.2f ", total);

            //process for item one
            System.out.println("Enter the name of taco 1");
            String taco = keyboard.nextLine();
            System.out.println("Enter taco's price");
            double price = Double.parseDouble(keyboard.nextLine());

            System.out.println("Enter the name of taco 2");
            String taco2 = keyboard.nextLine();
            System.out.print("Enter taco's price\n");
            double price2 = Double.parseDouble(keyboard.nextLine());

            System.out.println("Enter the name of taco 3");
            String taco3 = keyboard.nextLine();
            System.out.println("Enter taco's price");
            double price3 = Double.parseDouble(keyboard.nextLine());

            System.out.println("Enter the name of taco 4");
            String taco4 = keyboard.nextLine();
            System.out.println("Enter taco's price");
            double price4 = Double.parseDouble(keyboard.nextLine());

            System.out.println("Enter the name of taco 5");
            String taco5 = keyboard.nextLine();
            System.out.print("Enter taco's price\n");
            double price5 = Double.parseDouble(keyboard.nextLine());

            System.out.println("Enter the name of taco 6");
            String taco6 = keyboard.nextLine();
            System.out.println("Enter taco's price");
            double price6 = Double.parseDouble(keyboard.nextLine());

            System.out.println("Enter the name of taco 7");
            String taco7 = keyboard.nextLine();
            System.out.println("Enter taco's price");
            double price7 = Double.parseDouble(keyboard.nextLine());

            System.out.println("Enter the name of taco 8");
            String taco8 = keyboard.nextLine();
            System.out.print("Enter taco's price\n");
            double price8 = Double.parseDouble(keyboard.nextLine());

            System.out.println("Enter the name of taco 9");
            String taco9 = keyboard.nextLine();
            System.out.println("Enter taco's price");
            double price9 = Double.parseDouble(keyboard.nextLine());

            System.out.println("Enter the name of taco 10");
            String taco10 = keyboard.nextLine();
            System.out.println("Enter taco's price");
            double price10 = Double.parseDouble(keyboard.nextLine());

            System.out.println("Sorted tacos are");

Answer 1

您应该创建一个类来表示您的炸玉米饼，如下所示：

public class Taco {
public String name;
public double price;

public Taco() {}

Taco(String name, double price){
    this.name  = name;
        this.price = price;
    }
}

然后您可以使用 Collections.sort() 对它们进行排序，并将比较器传递给它：

import java.util.Scanner;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Comparator;

public class Test {
public static void main(String[] args) {
    // Write a program that sorts prices of 10 tacos in ascending order
    // based on the price, using arrays

    ArrayList<Taco> tacos = new ArrayList<>();
    Scanner keyboard = new Scanner(System.in);

    System.out.println("Welcome to the taco price sorter! Enter 10 taco names and prices and I'll sort it!");

    // Loop 10 times.
    for( int i = 0; i < 10; i++ ){
        // Get the name for each new item
        System.out.println("Enter the name of taco " + (i + 1) );
        String taco = keyboard.nextLine();
        System.out.println("Enter taco's price");
        double price = Double.parseDouble(keyboard.nextLine());
        Taco t = new Taco(taco, price);

        // Add it to our array list.
        tacos.add(t);
    }

    //Sort the list:
    Collections.sort(tacos, new Comparator<Taco>(){
         public int compare(Taco o1, Taco o2){
             if(o1.price == o2.price)
                 return 0;
             return o1.price < o2.price ? -1 : 1;
         }
    });


    System.out.println("Sorted tacos are:");
    for( Taco t : tacos ){
        System.out.println("Taco Prices: " + t.name + " " + t.price );
    }

    keyboard.close();
}
}

Answer 2

您可以创建一个名为 Taco 的类。

一旦用户输入了价格和名称，您就可以启动 Taco 类的对象并分配值。

将所有对象保存在一个数组中。

并使用排序算法。

Answer 3

为 taco 创建一个单独的类。然后创建name 和price 作为其成员变量。现在将 taco 的实例创建为数组。喜欢taco tacoInst[10]。现在您可以参考每个 taco 的价格为tacoInst[0].price。现在，当您对价格进行排序时，名称会自动排序。反之亦然。

Answer 4

要添加到上面人们的答案，是的 - 你应该开发一个 Taco 类，为什么不尝试实现 Comparable？我不确定你的 java 有多先进，以及你是否已经完成了接口，但看看你已经设置的问题的级别，它似乎会给你一些可靠的额外信用/炫耀信用。

您可以在 Enno Shioji 的回答 here（第一个）中找到一个很好的例子。基本上你要做的是声明 Taco implements Comparable<Taco> 然后覆盖 compareTo 方法。这将允许您使用 Collections.sort(tacos); 自动对 tacos 进行排序（这里数组的名称是 tacos，如果您调用它，例如 tacoArray，则命令将是 Collections.sort(tacoArray);）

编辑：除了 JB Nizet 在此答案下方的评论之外，我在这里尝试做的是标记您可能不熟悉的新 Java 技术。他完全正确，因为它不是世界上见过的最伟大的实现，我的逻辑是，如果你不知道这些东西，那么它可能会带来一个有趣的挑战。