java - 如何从左到右跟踪和移动字符串？

Question

我正在使用字符串制作赛车游戏，但无法让它们向右移动。我该如何移动琴弦？ 方法 JamesMove() 和 KeithMove() 与 SusanMove() 相同，只是变量名称不同。

public class NameRacer {
    public static  void nameRaces() {   
        Scanner scan = new Scanner(System.in);
        String response;
        int SusanFront, SusanBack, JamesFront, JamesBack, KeithFront, KeithBacck;
        boolean raceIsDone; 
        int move = (int)((Math.random() * 5) + 1);
        introduction();
        scan.nextLine();
        do {
            SusanMove();
            JamesMove();
            KeithMove();

            SusanMove();
            JamesMove();
            KeithMove();

            SusanMove();
            JamesMove();
            KeithMove();

            SusanMove();
            JamesMove();
            KeithMove();

            SusanMove();
            JamesMove();
            KeithMove();

            SusanMove();
            JamesMove();
            KeithMove();

            SusanMove();
            JamesMove();
            KeithMove();

            SusanMove();
            JamesMove();
            KeithMove();

            SusanMove();
            JamesMove();
            KeithMove();

            SusanMove();
            JamesMove();
            KeithMove();

            SusanMove();
            JamesMove();
            KeithMove();

            SusanMove();
            JamesMove();
            KeithMove();

            SusanMove();
            JamesMove();
            KeithMove();

            SusanMove();
            JamesMove();
            KeithMove();

            System.out.println("Would you like to watch the race again?");
            response=scan.next();
    }
        while(response.equalsIgnoreCase("yes"));
    }
    private static void introduction() {
        System.out.println("This game races three names. The random number generator");
        System.out.println("from the Math class repeatedly gives each name a random number");
        System.out.println("between 1 and 5. As the names move these random distances");
        System.out.println("we see which name gets to the finish line first.");
        System.out.println("Press a key to begin the race.");
    }  
    private static void SusanMove() {
        String SusanFrontString="";
        String SusanBackString="";

        int SusanFront=50,SusanBack=0;
        int move = (int)((Math.random() * 5) + 1);

        SusanFront=SusanFront-move;
        SusanBack=SusanBack+move;

        for(int back = 0; back<SusanBack;back++) {
            SusanBackString = SusanBackString+" ";
        }
        for(int front = 0; front<SusanFront;front++) {
            SusanFrontString = SusanFrontString+" ";
        }
        String SusanRace = SusanBackString+"Susan"+SusanFrontString+"|";
        System.out.println(SusanRace);
    }

我期望的输出是这样的:

Susan                        |
James                        |
Keith                        |

   Susan                     |
 James                       |
     Keith                   |

       Susan                 |
       James                 |
          Keith              |

但我得到的是:

 Susan                       |
     James                   |
  Keith                      |
     Susan                   |
   James                     |
 Keith                       |
  Susan                      |
  James                      |
 Keith                       |
  Susan                      |
 James                       |
   Keith                     |

Answer 1

您没有在任何地方存储赛车手的位置。从您的代码中，每次调用 *Move 方法就像您的赛车每次重新启动一样。每次调用时，您的 *Front 和 *Back 值始终会重新初始化为 50 和 0。

要解决这个问题，只需将默认值存储在 NameRaces 类中，并在 *Move 方法中删除这些变量的初始化，如下所示:

public class NameRacer {
    private static int SusanFront = 50, JamesFront = 50, KeithFront = 50;
    private static int SusanBack = 0, JamesBack = 0, KeithBack = 0;

    public static  void nameRaces() {   
        Scanner scan = new Scanner(System.in);
        String response;

        boolean raceIsDone; 
        int move = (int)((Math.random() * 5) + 1);
        introduction();
        scan.nextLine();
        do {
            SusanMove();
            JamesMove();
            KeithMove();
            System.out.println();

            SusanMove();
            JamesMove();
            KeithMove();
            System.out.println();

            SusanMove();
            JamesMove();
            KeithMove();
            System.out.println();

            SusanMove();
            JamesMove();
            KeithMove();
            System.out.println();

            SusanMove();
            JamesMove();
            KeithMove();
            System.out.println();

            SusanMove();
            JamesMove();
            KeithMove();
            System.out.println();

            SusanMove();
            JamesMove();
            KeithMove();
            System.out.println();

            SusanMove();
            JamesMove();
            KeithMove();
            System.out.println();

            SusanMove();
            JamesMove();
            KeithMove();
            System.out.println();

            SusanMove();
            JamesMove();
            KeithMove();
            System.out.println();

            SusanMove();
            JamesMove();
            KeithMove();
            System.out.println();

            SusanMove();
            JamesMove();
            KeithMove();
            System.out.println();

            SusanMove();
            JamesMove();
            KeithMove();
            System.out.println();

            SusanMove();
            JamesMove();
            KeithMove();
            System.out.println();

            System.out.println("Would you like to watch the race again?");
            response=scan.next();
    }
        while(response.equalsIgnoreCase("yes"));
    }
    private static void introduction() {
        System.out.println("This game races three names. The random number generator");
        System.out.println("from the Math class repeatedly gives each name a random number");
        System.out.println("between 1 and 5. As the names move these random distances");
        System.out.println("we see which name gets to the finish line first.");
        System.out.println("Press a key to begin the race.");
    }  
    private static void SusanMove() {
        String SusanFrontString="";
        String SusanBackString="";

        // Removed re-initialization of Front and Back values
        int move = (int)((Math.random() * 5) + 1);

        SusanFront=SusanFront-move;
        SusanBack=SusanBack+move;

        for(int back = 0; back<SusanBack;back++) {
            SusanBackString = SusanBackString+" ";
        }
        for(int front = 0; front<SusanFront;front++) {
            SusanFrontString = SusanFrontString+" ";
        }
        String SusanRace = SusanBackString+"Susan"+SusanFrontString+"|";
        System.out.println(SusanRace);
    }