java - 为什么我的 Java 程序只读取一行输入？

Question

这可能是一个非常简单的问题，但我一生都无法弄清楚出了什么问题。我刚刚开始使用这个自学 Java:http://math.hws.edu/javanotes/

作为引用，该程序依赖于该教科书中名为“TextIO”的输入/输出类。您可以在这里找到它的代码:http://math.hws.edu/javanotes/source/TextIO.java .

我制作了一个 super 简单的二十一点程序，我决定尝试跟踪高分:赢得的游戏数量和总金额。该程序应该从文本文件中读取分数，然后当用户获得更高分数时将信息重写到该文本文件中。

无论如何，一切似乎都运行良好，除了我希望您能够输入您赢得最多游戏或最多金钱的名字。我对它进行了 super 简化，使它只询问你的名字两次，试图看看问题是什么(而不是只询问你是否真的得到了高分)，问题是它两次打印问题“输入你的名字”，但只读取输入一次，奇怪的是它只读取第一次的输入!代码如下:

/* This program allows the user to play a game of 
enter code here`* blackjack against the computer. The user can bet money
* the game will keep track of total winnings as well as
* the number of games won.
*/
public class BlackjackGame {

    //keep track of highest scoring players so far
    static String nameForGames; //name of person who won most games
    static String nameForWinnings;  //name of person who won most money
    static int maxGames;        //highest # of games won
    static int maxWinnings;     //highest amount of money earned


    static int gamesWon = 0;    //keeps track of total games won by user
    static int money = 100;     //total pot of money available for betting
    private static Deck deck = new Deck();  
    static boolean wantToPlay;  //answers whether the user wants to keep playing

    public static void main(String[] args) {

        //load the high score data from the scores.txt file
            TextIO.readFile("scores.txt");
    nameForGames = TextIO.getlnString();
    maxGames = TextIO.getlnInt();
    nameForWinnings = TextIO.getlnString();
    maxWinnings = TextIO.getlnInt();

        TextIO.putln(nameForGames + " " + maxGames + " " + nameForWinnings + " " + maxWinnings);

    TextIO.readStandardInput();

    introduction();

    TextIO.put("Would you like to play");
    wantToPlay = TextIO.getBoolean();

    //user can keep playing indefinitely until they decide to stop
    while (wantToPlay == true) {
        playGame();
        if (wantToPlay == false) {
            break;
        }
        TextIO.put("Play again?");
        wantToPlay = TextIO.getBoolean();
    }

    //print results of gameplay
    TextIO.putln("\nThanks for playing!");
    TextIO.putln("You won " + gamesWon + " games and walk away with $" + money + ".");
    TextIO.putln();

//THIS IS THE PART THAT DOESNT MAKE SENSE? WHY IS IT ONLY READING INPUT ONCE?       
    TextIO.put("Enter your name: ");
    nameForWinnings = TextIO.getln();

    TextIO.putln();

    TextIO.put("Enter your name: ");
    nameForGames = TextIO.getln();

//Save new high scores to scores.txt.
    TextIO.writeFile("scores.txt");
    TextIO.putln(nameForGames);
    TextIO.putln(maxGames);
    TextIO.putln(nameForWinnings);
    TextIO.putln(maxWinnings);

    //Re-read the data from the file, and display to the player.
    System.out.println("The high scores are:");
    TextIO.readFile("scores.txt");
    nameForGames = TextIO.getlnString();
    maxGames = TextIO.getlnInt();
    nameForWinnings = TextIO.getlnString();
    maxWinnings = TextIO.getlnInt();

    TextIO.writeStandardOutput();
    TextIO.putln(nameForGames + " won " + maxGames + " games!");
    TextIO.putln(nameForWinnings + " won $" + maxWinnings + " total cash!");

} //end main()

Answer 1

看来您在读取用户名之前调用的 getBoolean 方法不会从流中删除行分隔符。这意味着第一次调用 readln 将返回该行剩下的内容，即使它是一个空字符串。查看可用的方法，您可能应该使用 getlnBoolean 来代替。