如何从LinkedList获取数据

Question

下面是我正在为我的程序寻找的一个示例输出。

示例输出

在每行输入体育场名称和比赛收入

完成后输入完成

巨人1000

Foxboro 500

巨人1500

完成

输入体育场名称以获取的总收入

巨人

总收入为2500.00

除了最后的总收入，我什么都做得很好。我不知道如何进入我的链接列表，获取游戏收入并显示它。这是我现在的代码，我一直在处理。。。

import java.util.LinkedList;
import java.util.Scanner;

public class LinkedLists {
    private final Scanner keyboard;

    private final LinkedList<String> stadiumNames;
    private final LinkedList<Integer> gameRevenue;

    public LinkedLists() {
        this.keyboard = new Scanner(System.in);
        this.stadiumNames = new LinkedList<String>();
        this.gameRevenue = new LinkedList<Integer>();
    }
    public void addData(String stadium, int revenue){
        stadiumNames.add(stadium);
        gameRevenue.add(revenue);
    }
    public void loadDataFromUser() {
        System.out.println("On each line enter the stadium name and game revenue.");
        System.out.println("Enter done when you are finished.");
        boolean done = false;
        while(!done) {
            System.out.print("Enter the name of the stadium:");
            String stadium = keyboard.next();
            if (stadium.equals("done")) {
                done = true;
            } else {
                System.out.print("Enter game revenue: ");
                addData(stadium, keyboard.nextInt());
            }
        }
    }
    // return -1 if not found
    public int getIndexForName(String name) {
        if(stadiumNames.contains(name)){
            System.out.println("The total revenue is: " +gameRevenue.get(0));
            System.exit(0);
        }
        return -1;
    }

    public void showInfoForName(String name) {
        int index = getIndexForName(name);
        if (index==-1) {
            System.out.println("There is no stadium named " + name);
        } else {
        }
    }
    public void showInfoForName() {
        System.out.println("Enter the name of the stadium to get the total revenue for it.");
        showInfoForName(keyboard.next());
    }
    public static void main(String[] args) {
        LinkedLists pgm = new LinkedLists();
        pgm.loadDataFromUser();
        pgm.showInfoForName();
    }
}

Answer 1

试试这个：

public int getIndexForName(String name) {
    if (stadiumNames.contains(name)) {
        int total = 0;
        for (int i = 0 ; i < stadiumNames.size() ; i++)
            if (stadiumNames.get(i).equals(name))
                total += gameRevenue.get(i);
        System.out.println("The total revenue is: " + total);
        System.exit(0);
    }
    return -1;
}

不过，还有更好的方法可以做到这一点。我可能会使用Map，将每个体育场名称映射到其总收入。您可以使用addData方法更新此映射。

Answer 2

使用哈希图要干净得多，而且你可以把总数保存在一边，而不用计算：

import java.util.Scanner;
import java.util.Map;
import java.util.HashMap;
/**
 * User: user
 * Date: 09/09/2012
 */
public class Blah {
    private Scanner keyboard;
    private Map<String, Integer> stadiumRevenues;
    private Integer total = 0;
    public Blah() {
        this.keyboard = new Scanner(System.in);
        this.stadiumRevenues = new HashMap<String, Integer>();
    }
    public void addData(String stadium, int revenue){
        stadiumRevenues.put(stadium, revenue);
        total += revenue;
    }
    public void loadDataFromUser() {
        System.out.println("On each line enter the stadium name and game revenue.");
        System.out.println("Enter done when you are finished.");
        boolean done = false;
        while(!done) {
            System.out.print("Enter the name of the stadium:");
            String stadium = keyboard.next();
            if (stadium.equals("done")) {
                done = true;
            } else {
                System.out.print("Enter game revenue: ");
                addData(stadium, keyboard.nextInt());
            }
        }
    }
    public int getTotal() {
        return total;
    }
    // return -1 if not found
    public int getIndexForName(String name) {
        Integer rev = stadiumRevenues.get(name);
        if(rev != null){
            System.out.println("The total revenue is: " +rev);
            System.exit(0);
        }
        return -1;
    }
    public void showInfoForName(String name) {
        Integer rev = stadiumRevenues.get(name);
        if (rev == null) {
            System.out.println("There is no stadium named " + name);
        } else {
        }
    }
    public void showInfoForName() {
        System.out.println("Enter the name of the stadium to get the total revenue for it.");
        showInfoForName(keyboard.next());
    }
    public static void main(String[] args) {
        Blah pgm = new Blah();
        pgm.loadDataFromUser();
        pgm.showInfoForName();
    }

}