Java 程序陷入用户输入循环

Question

我正在创建一个小型“游戏”程序，其中玩家输入楼层/房间号，但是当玩家猜测时，它会卡住并在单个玩家上循环，并且不会移动到下一个玩家，也不会判断玩家对狗被关在建筑物中的位置的猜测是否正确。

PuppyPlay.java:

import java.util.Random;
import java.util.Scanner;

/**
 * This program is used as a driver program to play the game from the
 * class LostPuppy.
 *
 * A puppy is lost in a multi-floor building represented in the class 
 * LostPuppy.class.  Two players will take turns searching the building
 * by selecting a floor and a room where the puppy might be.
 *
 */

public class PuppyPlay{
  /**
   * Driver program to play LostPuppy.
   *
   * @param theArgs may contain file names in an array of type String
   */
  public static void main(String[] theArgs){
    Scanner s = new Scanner(System.in);
    LostPuppy game; 
    int totalFloors;
    int totalRooms;
    int floor;
    int room;
    char[] players = {'1', '2'};
    int playerIndex;
    boolean found = false;
    Random rand = new Random();

    do {
      System.out.print("To find the puppy, we need to know:\n"
                       + "\tHow many floors are in the building\n"
                       + "\tHow many rooms are on the floors\n\n"
                       + "             Please enter the number of floors: ");
      totalFloors = s.nextInt();
      System.out.print("Please enter the number of rooms on the floors: ");
      totalRooms = s.nextInt();
      s.nextLine();    // Consume previous newline character    

      // Start the game: Create a LostPuppy object:
      game = new LostPuppy(totalFloors, totalRooms);

      // Pick starting player
      playerIndex = rand.nextInt(2);

      System.out.println("\nFloor and room numbers start at zero '0'");

      do {

        do {
          System.out.println("\nPlayer " + players[playerIndex]
                             + ", enter floor and room to search separated by a space: ");
          floor = s.nextInt();
          room = s.nextInt();

          //for testing, use random generation of floor and room
          //floor = rand.nextInt(totalFloors);
          //room = rand.nextInt(totalRooms);
        } while (!game.indicesOK(floor, room) 
                 || game.roomSearchedAlready(floor, room));


        found = game.searchRoom(floor, room, players[playerIndex]);
        playerIndex = (playerIndex + 1) % 2;
        System.out.println("\n[" + floor + "], [" + room + "]");
        System.out.println(game.toString());
        s.nextLine();
      } while (!found);

      playerIndex = (playerIndex + 1) % 2;
      System.out.println("Great job player " + players[playerIndex] +"!");
      System.out.println("Would you like to find another puppy [Y/N]? ");
    } while (s.nextLine().equalsIgnoreCase("Y"));
  }
}

LostPuppy.java:

import java.util.Random; // Randomize the dog placement in building
import java.util.Scanner; // User input

/**
 * This program is used as a program to play the game from the
 * driver PuppyPlay.java
 *
 * A puppy is lost in a multi-floor building represented in the class 
 * LostPuppy.class.  Two players will take turns searching the building
 * by selecting a floor and a room where the puppy might be.
 *
 */

 public class LostPuppy{

   private char[][] myHidingPlaces; // Defining class fields for assignment
   private int myFloorLocation;
   private int myRoomLocation;
   private char myWinner;
   private boolean myFound;

   /**
   * Creates constructor takes floor/room numbers inputted by user
   *
   * @param theFloors for number of floors
   * @param theRooms for number of rooms
   */

   public LostPuppy(int theFloors, int theRooms) {
      Random random = new Random();
      myHidingPlaces = new char[theFloors][theRooms];

      // Filling array with spaces
      int i;
      for (i = 0; i < theFloors; i++) {
         for (int k = 0; k < theRooms; k++) {
            myHidingPlaces[i][k] = ' ';
         }   
      }

      myFloorLocation = random.nextInt(theFloors);
      myRoomLocation = random.nextInt(theRooms);
      myHidingPlaces[myFloorLocation][myRoomLocation] = 'P';
      myWinner = ' ';
      myFound = false;
   }

   /**
   * Checks if room has been searched prior
   *
   * @param theFloors for number of floors
   * @param theRooms for number of rooms
   */

   public boolean roomSearchedAlready(int theFloors, int theRooms) {
      boolean searchedRoom;
      if (myHidingPlaces[theFloors][theRooms] == ' ') {
         myHidingPlaces[theFloors][theRooms] = 'S';
         searchedRoom = false;
      } else {
         searchedRoom = true;
      }  
      return searchedRoom;
      }

   /**
   * Checks if the puppy has been found
   *
   * @param theFloors for number of floors
   * @param theRooms for number of rooms
   */

   public boolean puppyLocation(int theFloors, int theRooms) {
      if (myHidingPlaces[myFloorLocation][myRoomLocation] == myHidingPlaces[theFloors][theRooms]) {
         myFound = true;
      } else {
         myFound = false;
      }      
      return myFound;
      }

   /**
   * Checks if floors and rooms won't throw out of bounds error
   *
   * @param theFloors for number of floors
   * @param theRooms for number of rooms
   */

   public boolean indicesOK(int theFloors, int theRooms) {
      boolean indicesFit;
      if (theFloors < numberOfFloors() && theRooms < numberOfRooms()) {
         indicesFit = true;
      } else {
         indicesFit = false;
      }
      return indicesFit;
      }

   /*
   * Checks # of floors and returns it
   */

   public int numberOfFloors() {
      return myHidingPlaces.length;
      }

   /*
   * Checks # of rooms and returns it
   */

   public int numberOfRooms() {
      return myHidingPlaces[0].length;
      }

   /**
   * Checks which player found the dog and won, or if not checks to see what player
   * guessed wrong and puts their # in the box
   *
   * @param theFloors for number of floors
   * @param theRooms for number of rooms
   * @param thePlayer for 1st or 2nd player
   */

   public boolean searchRoom(int theFloors, int theRooms, char thePlayer) {
      if (myHidingPlaces[myFloorLocation][myRoomLocation] == myHidingPlaces[theFloors][theRooms]) {
         myFound = true;
         myWinner = thePlayer;
      } else {
         myHidingPlaces[theFloors][theRooms] = thePlayer;
         myFound = false;
      }      
      return myFound;
      }

   /*
   * toString displays the current hidingPlaces array and it’s contents EXCEPT 
   * the location of the puppy which remains hidden until he/she is found at 
   * which point toString will be called (by the driver) and both the player 
   * who found the puppy and a ‘P’ will be displayed in the same cell….
   *
   *
   *
   */

   public String toString() {
      return null;
      }
 }

要运行此代码，您需要将两个代码及其各自的发布名称放在一起，并在同一文件夹中运行 PuppyPlay.java 和 LostPuppy.java(仅供引用)。

Answer 1

问题出在PuppyPlay的这个地方:

    found = game.searchRoom(floor, room, players[playerIndex]);
    playerIndex = (playerIndex + 1) % 2;
    System.out.println("\n[" + floor + "], [" + room + "]");
    System.out.println(game.toString());
    s.nextLine();

所以你的程序希望你在这里输入一些东西，它会一直等待，直到你按下回车键，所以你可以删除该行:s.nextLine();