所以我正在努力制作一款像Fort of Fortune / Hangman这样的简单游戏。用户输入1表示输入字母，输入2表示解决，输入3表示退出。当我输入这封信时，我收到一个错误：
Enter your choice:
(1) to guess a letter
(2) to solve the puzzle
(3) to quit
1
Please enter your letter
b
Exception in thread "main" java.lang.StringIndexOutOfBoundsException: String index out of range: 8
at java.lang.AbstractStringBuilder.charAt(Unknown Source)
at java.lang.StringBuilder.charAt(Unknown Source)
at Puzzle.<init>(Puzzle.java:68)
at PuzzleTester.main(PuzzleTester.java:50)
当我进入解决方案时，我得到了同样的错误。 退出选项工作正常。那么这些错误是什么呢？
Puzzle.java：
/**
* A puzzle is used to represent a word puzzle. A puzzle contains a solution
* and the current state of the puzzle. The current state of the puzzle is
* represented with a hyphen for each letter in the puzzle that has not yet been
* guessed. For example if a puzzle is created like this:
*
* Puzzle puzzle = new Puzzle("BIG JAVA");
*
* a call to puzzle.getPuzzle() should return: --- ----
*
* Notice that all letters in the solution were replaced with hyphens but the
* space character remained in place.
*
* A call to puzzle.guessLetter('b') should return 1 and a subsequent
* call to puzzle.getPuzzle() should return: B-- ----
*
* Calling puzzle.guessLetter('b') a second time should return 0 since the
* letter B has already been guessed and should leave the puzzle unchanged.
*
* <p/>
* Bugs: (List any known issues or unimplemented features here)
*
* @author (Insert your first and last name)
*
*/
public class Puzzle
{
/** The solution is the complete word or phrase that is to be guessed */
private String solution="BIG JAVA";
/**
* The puzzle is the word or phrase that is to be guessed with hyphens for
* all unguessed letters. Initially the puzzle should include all hyphens
* for all letters in the solution. As the user guesses a letter the hyphens
* for that letter are replaced with the letter.
*/
private StringBuilder puzzle;
/**
* Constructs a new Puzzle object with the given puzzle solution. Puzzles
* can contain any character and should be case insensitive. This
* constructor should set the current state of the puzzle so the all letters
* in the puzzle are set to a hyphen. All non letter values should be left
* unchanged in the puzzle. The puzzle should be set to the solution passed
* in.
*
* @param solution the solution to the puzzle
*/
public Puzzle(String Solution)
{
puzzle=new StringBuilder(this.solution);
int length= this.solution.length();
for(int count=0; count<=length; count++)
{
if (Character.isLetter(puzzle.charAt(count)))
{
puzzle.setCharAt(count, '-');
}
}
}
/**
* The guessLetter method is used to determine how many times the letter
* that is passed in occurs in the puzzle. If the letter has already been
* guessed previously, this method should return zero. This method should be
* case insensitive. In other words 'H' is the same as 'h'. After a call to
* to this method the puzzle should be updated to remove the hyphen from
* the location in the puzzle for each occurrence of the letter.
*
* @param letter
* the letter that the user is guessing
* @return the number of times the letter occurs in the solution only if the
* letter has not already been guessed. If the letter has been
* previously guessed this method should return 0.
*/
public int guessLetter(char letter)
{
int count = 0;
int k=this.solution.length();
solution.equalsIgnoreCase(solution);
for(int seq=0; seq<=k; seq++)
{
if(solution.charAt(seq)==letter)
{
count++;
puzzle.setCharAt(seq, letter);
}
}
return count;
}
/**
*
* The getPuzzle method should return the current state of the puzzle. The
* puzzle should include a hyphen for any letters that have not been guessed.
*
* @return the current state of the puzzle
*/
public String getPuzzle()
{
String str=new String(puzzle);
return str;
}
/**
* The solvePuzzle method is used to verify that a solution passed in
* matches the solution to this puzzle. The check for matching solutions
* should be case insensitive.
*
* @param solution
* @return true if the solution passed in matches the solution for the
* puzzle
*/
public boolean solvePuzzle(String solution)
{
if(this.solution==solution)
{
return true;
}
else
{
return false;
}
}
}
Puzzletester.java：
import java.util.Scanner;
public class PuzzleTester
{
/**
* (Insert a brief description that describes the purpose of this method)
*
* @param args
*/
public static void main(String[] args)
{
String str="";
Scanner input= new Scanner(System.in);
System.out.println("Enter your choice: ");
System.out.println("(1) to guess a letter");
System.out.println("(2) to solve the puzzle");
System.out.println("(3) to quit");
int choice=input.nextInt();
while(choice!=3)
{
if(choice==1)
{
System.out.println("Please enter your letter");
str=input.next();
char letter=str.charAt(0);
Puzzle game=new Puzzle(str);
game.guessLetter(letter);
}
if(choice==2)
{
System.out.println("Please solve the puzzle");
input.nextLine();
String solution=input.next();
Puzzle game=new Puzzle(solution);
game.solvePuzzle(solution);
}
}
if(choice==3)
{
System.out.println("Good Bye");
}
}
}
答案 0 :(得分：3)
Puzzle类构造函数中的for循环是罪魁祸首：
for(int count=0; count<=length; count++)
您的情况应该是<而不是<=。由于您的索引从0开始，因此您可以访问的字符串的最后一个索引是string.length() - 1。因此，您不应该迭代到length，而只能到值1 less than length。
所以，将其改为：
for(int count=0; count < length; count++)
同样是guessLetter方法：
for(int seq=0; seq<=k; seq++) // Change here too
此外，仅在您的guessLetter方法中，我不明白您在for statement之前要对此声明做些什么：
solution.equalsIgnoreCase(solution);
您没有将值分配给任何变量，也没有在任何地方使用它。按照目前的情况，上述比较是没用的。
答案 1 :(得分：1)
你循环
for(int count=0; count<=length; count++)
应该是
for(int count=0; count<length; count++)