我正在尝试制作一个刽子手游戏。在每个回合，用户猜一个字母。如果他们猜对了，他们可以再次猜测。否则，他们剩余的可用猜测会逐一减少，并且猜到的字母会被放入一个数组中。
当用户点击零剩余猜测时，该程序应该询问他们是否想再次玩。如果他们回答是，则应该重新启动游戏，如果他们回答否，则程序结束。
我遇到的问题是持有猜测的数组，以及重启游戏。
此外，程序在启动时会偶尔出错。错误是
Hangman1.main中的线程“main”java.lang.NullPointerException中的异常（Hangman1.java:27）
尝试重新启动游戏时的错误是
Hangman1.main中的线程“main”java.lang.NullPointerException中的异常（Hangman1.java:101）
searchArray是应该采用char数组的位置并将其复制到星号数组并返回星号数组的方法，这似乎不起作用。运行调试似乎导致程序崩溃的问题是该单词有时会以null结尾，但有时只是我不知道为什么
import java.util.*;
import java.io.*;
public class Hangman1 {
static Scanner keyboard = new Scanner(System.in);
public static final int MAXSIZE = 15000;
public static final int NUM_GUESS = 8;
public static final int WORD_LENGTH = 20;
public static void main(String[] args) {
int random = pickrandom(MAXSIZE);
try {
// Set up connection to the input file
Scanner input = new Scanner(new FileReader("dictionary.txt"));
instructions();
keyboard.nextLine();
clearScreen();
String word = randomWord(input, random);
System.out.println(word);
String[] charArray = word.split("");
System.out.print("\n");
String[] asterisk = asteriskLine(word);
String decision = "Y";
//decision = keyboard.nextLine().toUpperCase();
System.out.println("Word to guess :");
for (int count = 0; count < word.length(); count++) {
System.out.print(asterisk[count]);
}
System.out.print("\n");
int tries = NUM_GUESS;
System.out.println("Enter a letter to guess or 9 to quit");
String guess = keyboard.next();
String[] wrongGuesses = new String [NUM_GUESS];
int guessMade = 0;
do {
//System.out.println(tries);
while (!(guess.equals("9")) && !(guess.equals(word)) && (tries > 0))
{
String letter = guess.substring(0,1);
if (word.indexOf(letter) < 0) {
clearScreen();
tries--;
wrongGuesses = wrongGuesses(guessMade, wrongGuesses, letter);
printArray(asterisk, charArray, word, tries, wrongGuesses, guessMade);
guessMade++;
guess = keyboard.next();
}
else {
clearScreen();
asterisk = searchArray(charArray, asterisk, guessMade, letter, word);
printArray(asterisk, charArray, word, tries, wrongGuesses, guessMade);
guess = keyboard.next();
}
if (charArray == asterisk) {
System.out.println("You won!");
}
if (tries == 0) {
System.out.println("You have no more guesses left");
}
}
if (guess.equals("9")) {
System.out.println("Thanks for playing");
}
System.out.println("Play again? Y/N");
decision = keyboard.next().toUpperCase();
if (decision.equals("Y")) {
random = pickrandom(MAXSIZE);
word = randomWord(input, random);
charArray = word.split("");
System.out.print("\n");
asterisk = asteriskLine(word);
guess = keyboard.next();
}
} while (decision.equals("Y"));
//System.out.println("Play again? Y/N");
//decision = keyboard.nextLine().toUpperCase();
}
catch (FileNotFoundException e) {
System.out.println("There was an error opening one of the files.");
}
}
//Clears screen after introduction
private static void clearScreen() {
for (int blanks = 0; blanks < 80; blanks++) {
System.out.println();
}
}
// This method returns a randomly selected integer
// between 0 and count-1
public static int pickrandom(int count) {
Random generator = new Random();
return generator.nextInt(count);
}
// Places asterisks in place of the letters in the word
// Parameter is the string word. it holds mystery word
public static String[] asteriskLine(String word) {
int i;
String[] asteriskArray = new String [word.length()];
for (i = 0; i < word.length(); i++) {
asteriskArray[i] = "* ";
}
return asteriskArray;
}
public static void instructions() {
System.out.println(" H A N G M A N. "
+ "\n This is a word guessing game. "
+ "\n A word will be selected at random and kept hidden. You will try to figure out the secret word by"
+ "\n guessing letters which you think are in the word. "
+ "\n You will guess one letter at a time. "
+ "\n If the letter you guess is correct, the position(s) of the letter in the secret word will be shown. "
+ "\n You will be allowed "
+ NUM_GUESS
+ " wrong guesses If you guess incorrectly "
+ NUM_GUESS
+ " times, you lose the game. "
+ "\n If you guess all of the letters in the word, you win."
+ "\n\n Press enter to continue ");
}
public static String randomWord(Scanner input, int random) {
String[] dictionaryWords = new String [MAXSIZE];
int usedsize = 0;
while (usedsize < MAXSIZE && input.hasNextLine()) {
dictionaryWords[usedsize] = input.nextLine();
usedsize++;
}
String word = dictionaryWords[random];
return word;
}
//Replaces correct guess in blanks
public static String correctWord(String guess, String word, String asterisk, char letter) {
return null;
}
public static void printArray(String[] asterisk, String[] charArray, String word, int tries, String[] wrongGuesses, int guessMade) {
System.out.println("Word to guess");
for (int count = 0; count < word.length(); count++) {
System.out.print(asterisk[count]);
}
System.out.println("\nGuesses remaining: " + tries);
System.out.print("Incorrect letters tried: ");
for (int count = 0; count <= guessMade; count++) {
System.out.print(wrongGuesses[count] + " ");
}
System.out.println("\nEnter a letter to guess or 9 to quit");
}
public static String[] wrongGuesses(int guessMade, String [] wrongGuesses, String letter) {
wrongGuesses[guessMade] = letter;
return wrongGuesses;
}
public static String[] searchArray(String[] charArray, String[] asterisk, int guessMade, String letter, String word) {
int[] a = new int[word.length()];
for (int count = 0; count < word.length(); count++) {
if (letter == charArray[count]) {
asterisk[count] = charArray[count];
}
}
return asterisk;
}
}
答案 0 :(得分：0)
您需要做的一件事就是只读一次所有单词，然后将它们全部存储到ArrayList中。您当前的代码尝试重新使用已经花费的Scanner对象，但这将失败。而是从ArrayList<String>获取随机单词。
答案 1 :(得分：0)
运行调试似乎导致程序崩溃的问题是 这个词有时候会以null为结尾，但有时候却没有 真的知道为什么
db.getCollection('raw_originBusinessData').aggregate([
{ "$match": {
objectStatus : "UNPROCESSED"
, $or: [
{ objectOriginAPI : "Profit & Loss"}
,{objectOriginAPI : "Balance Sheet"}
,{objectOriginAPI : "Bank Summary"}
]}
},
// don't worry about this, this is all good
{ "$unwind": "$objectRawOriginData.Reports" }
,{ "$unwind": "$objectRawOriginData.Reports.Rows" }
,{ "$unwind": "$objectRawOriginData.Reports.Rows.Rows" },
// this is where I believe I'm having my problem
{ "$group": {"_id": "$entity_id"
// , "$connection_id"
// , "objectCycleID"
, "accountBalances": { "$push": "$objectRawOriginData.Reports.Rows.Rows.Cells.Value" }
}},
{$project: {objectClass: {$literal: "Source Data"}
, objectCategory: {$literal: "Application"}
, objectType: {$literal: "Account Balances"}
, objectOrigin: {$literal: "Xero"}
, entity_ID: "$_id"
, connection_ID: "$connection_ID"
, accountBalances: "$accountBalances"}
}
]
// ,{$out: "std_sourceBusinessData"}
)
有时 public static String randomWord(Scanner input, int random) {
String[] dictionaryWords = new String [MAXSIZE];
int usedsize = 0;
while (usedsize < MAXSIZE && input.hasNextLine()) {
dictionaryWords[usedsize] = input.nextLine();
usedsize++;
}
String word = dictionaryWords[random];
return word;
}
会大于random。
所以你需要从循环外移动这一行
usedsize进入此函数，并且最大值为usedsize（或usedsize-1）。
您可以保护自己免受此错误的影响，并通过编写单元测试来确定您是否应该使用usedsize或usedsize-1。查看Junit教程。
在你的junit测试中，调用randomword并将其传递给一个非常高的随机值。然后
int random = pickrandom(MAXSIZE);
当随机长度超过字典长度时，Word为空。