如果这里的end=mid-1和begin=mid+1分别修改成end=mid和begin=mid,这段代码为什么会陷入死循环？

Question

相关代码：

public static <T extends Comparable<? super T>> int binarySearch2(T[] value,int begin,int end,T key){
        int index=1;
        while (begin<=end){
            int mid = (begin+end)/2;
            if (key.compareTo(value[mid])==0){
                System.out.println(index);
                return index;
            }
            if (key.compareTo(value[mid])<0){
                end = mid-1;
                index++;
            }
            else{
                begin=mid+1;
                index++;
            }
        }
        return index;
    }

psvm相关代码

Integer[] arr = new Integer[]{1,2,3,4,5,6,7,8,9,10,11,12,13};
        int begin = 1;
        int end = 9;
        int key = 13;
        System.out.println("遍历次数："+binarySearch2(arr,begin,end,key));

Answer 1

因为加入改成end=mid和begin=mid的话，begin就和end相等了，在while中进行条件判断的时候，总是为true