ArrayIndexOutOfBoundsException in Simon Game，无法弄清楚为什么

Question

我对Java很陌生，但一般不是OOP。我正在开发经典的 Simon 游戏，其中用户遵循我的 Java 类随机生成的模式（实际上是数字）的递增序列。我收到错误：

java.lang.ArrayIndexOutOfBoundsException: 20
at Simon.generateSequence(Simon.java:58)
at Simon.<init>(Simon.java:23)

我不知道如何解决这个问题。看起来我调用的元素并不比数组中的元素多。代码如下：

import acm.program.*;
import acm.graphics.*;
import java.awt.Color;
import java.awt.Font;
import javax.swing.*;
import java.awt.event.*;

public class Simon extends Program implements ActionListener
{
private int array[];
private int currentSeqLength;
private int usersInput;

public Simon()
{
    //Initialize Class Values
    array = new int[20];
    currentSeqLength = 1;
    usersInput = 0;
    generateSequence();
    while(currentSeqLength <= array.length)
    {
        playSequence();
        //Wait For User's Input Here, Assign To Variable
        //usersInput = 
        if (pushButton(usersInput)== true)
        {
            currentSeqLength++;
        }
        else
        {
            gameOverMessage();
            break;
            //Reset Variables:
        }
    }

}
public void generateSequence()
{
    //Fill Array With Random Numbers
    for (int i = 0; i <= array.length; i++ )
    {
        array[i] = (int)(Math.random()*4);
    }

}
public void setLength(int length)
{
    //Set Current Length To Size Of Given Argument
    currentSeqLength = length;
}
int getLength()
{
    return currentSeqLength;
}
int[] playSequence()
{
    //Print Out The Current Sequence
    //New Local Array To Return
    int newArray[]= new int[currentSeqLength];

    //Repeat As Many Times As Value Of currentSeqLength
    for(int i = 0; i <= currentSeqLength ; i++)
    {
        System.out.println(array[i]);
        //Return an array of int's to the player. 
        newArray[i] = array[i];
    }
    return newArray;
}
boolean pushButton(int usersInput)
{
    //Given A Button Press (0-3), Return Whether That Was The 
        //Correct Button To Play At The Moment
    if (usersInput == array[currentSeqLength])
    {
        return true;
    }
    else
    {
        return false;
    }

}
boolean isTurnOver()
{
    //If Current Sequence Length Matches Or Exceeds Value Of 
        //Array Element In Location Of Current Sequence Length
    if (currentSeqLength >= array[currentSeqLength])
    {
        return true;
    }
    else
    {
        return false;
    }
}
//Not Needed?
boolean isGameOver()
{
    if (pushButton(usersInput) == false)
    {
        return true;
    }
    else
    {
        return false;
    }
}
String gameOverMessage()
{
    return "Game Over";
}
/*public void actionPerformed(ActionEvent event)
{
    int input;

}
*/

}

Answer 1

for (int i = 0; i <= array.length; i++ )
    {
        array[i] = (int)(Math.random()*4);
    }

您正在从 0 循环到 20。20 是数组的长度，21 是这个 for 循环将执行的迭代次数。

将 <= 替换为 <。