如何将参数传递给另一个类中的数组？

Question

这是我第一次在StackOverflow上发帖，但是我已经访问了很多次。 我正在上一门计算机科学课，但遇到了一个无法通过研究解决的问题。 任务是创建一个带有实例变量和构造函数的NBATeam类，以及一个NBA客户端，该客户端从用户那里接收球员名称的参数并将其传递给第一类的数组。

所以我遇到的问题是运行程序时，我输入播放器名称并将其传递给数组，第一个名称数组被删除。 但是，输入到最新数组中的名称是可以的。

抱歉，如果我的术语错误，我仍然是新手！

非常感谢您能给我的任何帮助。

我将在下面插入我的代码。 我的问题是它说[null] 。 我也进入了第一队的鲍勃和第二队的brian ，但是bob在第二队。

请帮忙！

Create NBA team of Heats
Add a player to team Heats? (yes/no)
yes
Enter the name of the player: 
bob
Add one more player to Heats?
no
Create NBA team of Spurs
Add a player to team Spurs? (yes/no)
yes
Enter the name of the player: 
brian
Add another player to Spurs?
no
***Heat Wins!***
Heats[null]Wins: 4 Loses: 0
Spurs[bob]Wins: 0 Loses: 4

---

import java.util.*;

public class NBA {
public static void main(String[] args) {
    Scanner input = new Scanner(System.in);
    String ifAddPlayer, playerName = null;


    //construct Team Heat
    System.out.println("Create NBA team of Heats");
    NBATeam heats = new NBATeam("Heats");
    System.out.println("Add a player to team Heats? (yes/no)");
    ifAddPlayer = input.next();

        while(ifAddPlayer.equalsIgnoreCase("yes")) {
            System.out.println("Enter the name of the player: ");

            heats.addPlayer(playerName);
            playerName = input.next();

            System.out.println("Add one more player to Heats?");
            ifAddPlayer = input.next();
        }

    //construct team Spurs.
    System.out.println("Create NBA team of Spurs");
    NBATeam spurs = new NBATeam("Spurs");
    System.out.println("Add a player to team Spurs? (yes/no)");
    ifAddPlayer = input.next();

        while(ifAddPlayer.equalsIgnoreCase("yes")) {
            System.out.println("Enter the name of the player: ");

            spurs.addPlayer(playerName);
            playerName = input.next();

            System.out.println("Add another player to Spurs?");
            ifAddPlayer = input.next(); 
        }

        playAGame(heats,spurs);
         System.out.println(heats.toString());
            System.out.println(spurs.toString());

}
public static void playAGame(NBATeam heats, NBATeam spurs) {

        for(int game = 0; game < 7; game++){

        double score = Math.random();

        if (score < .5) {
        heats.winAgame(spurs);

        }
        else{    
        spurs.winAgame(heats);

        }
        if(spurs.nWin()==4 || heats.nWin()==4) {
            break;
        }
        }
        if(spurs.nWin()>heats.nWin()) {
            System.out.println("***Spurs Win!***");
        }
        else
            System.out.println("***Heat Wins!***");
    }
}




import java.util.Arrays;

public class NBATeam {
private String sTeamName;
private int nWin;
private int nLoss;
private int nPlayer;

private String [] playerArray = new String[nPlayer];

public NBATeam(String sTeamName) {
    this.sTeamName = sTeamName;
    nPlayer=0;

}
public int nWin() {
    return nWin;
}
public int nLoss() {
    return nLoss;
}
public String getTeamName(){        
    //gets team's Name
    return sTeamName;
}

public String toString() {
     return sTeamName + Arrays.toString(playerArray)+ "Wins: " + nWin + 
            " Loses: " + nLoss;

}

public void lossAgame() {
    this.nLoss++;
}
public void winAgame(NBATeam team2) { //To win over the team
    nWin++;
    team2.setLoss(team2.nLoss()+1);
    //teamB.lossAgame();
}

public int getLossNumber() {
    return this.nLoss;
}
public void setLoss(int l) {
    this.nLoss=l;
}

public int getWinNumber() {
    return this.nWin;
}
public void setWin(int w) {
    this.nWin=w;
}
public void addPlayer(String player) {

    String temp[] = playerArray;
    playerArray = Arrays.copyOf(temp, temp.length+1);
    playerArray[nPlayer] = player;
    nPlayer++;

}

public String[] getPlayerArray() {
    return playerArray;
}

public void setPlayerArray(String[] playerArray) {
    this.playerArray = playerArray;
}
}

Answer 1

您从playerName的初始值null开始，然后在获取该值之前添加playerName 。 这个，

heats.addPlayer(playerName);
playerName = input.next();

被颠倒了 。 它应该是

playerName = input.next();
heats.addPlayer(playerName);

而且 ，你是一致的 。 这个，

spurs.addPlayer(playerName);
playerName = input.next();

同样被颠倒。 并且应该

playerName = input.next();
spurs.addPlayer(playerName);

我建议您限制变量的可见性。 如果你有

String playerName = input.next();
heats.addPlayer(playerName);

它将限制在设置播放器之前添加播放器的可能性。