binarySearch方法生成“ArrayIndexOutOfBounds”例外 [英] binarySearch Method producing "ArrayIndexOutOfBounds" Exception

问题描述

我想知道为什么这个方法给我一个 ArrayIndexOutOfBounds 异常，当我提供一个不是我的数组中的一个字母的键。如果密钥不是一个字母，它似乎没有问题返回值。

  public class BinarySearch2 {
 
 public static void main（String [] args）{
 String [] array = {A，B，C，D，E，F G，H，I，J}; 
 String key =K; 
 String found = binarySearch（array，key）; 
 System.out.println（found）; 
} 
 
 public static String binarySearch（String [] array，String key）{
 int low = 0; 
 int high = array.length; 
 int mid =（low + high）/ 2; 
 // int i = 0; 
 
 while（low< = high）{
 //System.out.print(i +）; 
 if（array [mid] .compareTo（key）< 0）{
 System.out.println（array [mid] .compareTo（key））; 
 low = mid + 1; 
 mid =（low + high）/ 2; 
} 
 else if（array [mid] .compareTo（key）> 0）{
 high = mid-1; 
 mid =（low + high）/ 2; 
} 
 else 
返回数组[mid]; 
 
 // i ++; 
} 
返回-1; 
} 
} 
  

解决方案

您的 binarySearch 方法，您已将高初始化为： -

int $ = $; $ pre> int low = 0;
int high = array.length;
int mid =（low + high）/ 2;


您的高实际上应该是： -

  int high = array.length  -  1; 
  

I would like to know why this method is giving me an ArrayIndexOutOfBounds exception when I provide a key that is a letter not in my array. It seems to have no problem returning a value if the key is anything other than a letter.

public class BinarySearch2 {

    public static void main(String[] args) {
        String[] array = {"A", "B", "C", "D", "E", "F", "G", "H", "I", "J"};
        String key = "K";
        String found = binarySearch(array, key);
        System.out.println(found);
    }

    public static String binarySearch(String[] array, String key) {
        int low = 0;
        int high = array.length;
        int mid = (low + high)/2;
        //int i = 0;

        while (low <= high) {
            //System.out.print(i + " ");
            if (array[mid].compareTo(key) < 0) {
                System.out.println(array[mid].compareTo(key));
                low = mid + 1;
                mid = (low + high)/2;
            }
            else if (array[mid].compareTo(key) > 0) {
                high = mid - 1;
                mid = (low + high)/2;
            }
            else
                return array[mid];

            //i++;
        }
        return "-1";
    }
}

解决方案

In your binarySearch method, you have initialized your high to: -

int low = 0;
int high = array.length;
int mid = (low + high)/2;

Your high should actually be: -

int high = array.length - 1;

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