二分查找的递归实现

import java.util.*;
//二分查找的递归实现
public class T4 {

	static int binarysearch(int[] arr, int low, int high, int key){
		int mid = (low + high) / 2;
		
		if(low > high)
			return -1;
		if(key > arr[mid])
			return binarysearch(arr, mid + 1, high, key);
		else if(key < arr[mid])
			return binarysearch(arr, low, mid - 1, key);
		else
			return mid;
		
	}
	
	public static void main(String[] args) {
		
		

		int[] arr = { 1, 2, 3, 4, 5, 6, 7, 8, 9 };
		
		int index = T4.binarysearch(arr, 0, 9, 9);
		System.out.println(index);
	}

}