如何將參數傳遞給另一個類中的數組？

Question

這是我第一次在StackOverflow上發帖，但是我已經訪問了很多次。 我正在上一門計算機科學課，但遇到了一個無法通過研究解決的問題。 任務是創建一個帶有實例變量和構造函數的NBATeam類，以及一個NBA客戶端，該客戶端從用戶那里接收球員名稱的參數並將其傳遞給第一類的數組。

所以我遇到的問題是運行程序時，我輸入播放器名稱並將其傳遞給數組，第一個名稱數組被刪除。 但是，輸入到最新數組中的名稱是可以的。

抱歉，如果我的術語錯誤，我仍然是新手！

非常感謝您能給我的任何幫助。

我將在下面插入我的代碼。 我的問題是它說[null] 。 我也進入了第一隊的鮑勃和第二隊的brian ，但是bob在第二隊。

請幫忙！

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

您從playerName的初始值null開始，然后在獲取該值之前添加playerName 。 這個，

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

被顛倒了 。 它應該是

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

而且 ，你是一致的 。 這個，

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

同樣被顛倒。 並且應該

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

我建議您限制變量的可見性。 如果你有

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

它將限制在設置播放器之前添加播放器的可能性。