给定一个有序整型数组, 实现二分查找

问题描述：给定一个有序整型数组, 实现二分查找

import java.util.Scanner;
import java. util. Arrays;

public class binaryTest {
    public static void main (String[] args) {
    	//输入需查找的数字
		Scanner scanner = new Scanner(System. in);
		int num = scanner.nextInt();
		int[] arr = {1, 2, 3, 4, 5, 6, 7, 8};
		//调用并输出
		System. out. println(binarySearch(arr, num));
    }
    //二分查找
    public static int binarySearch(int[] arr, int toFind) {
		int left = 0;
		int right = arr.length - 1;
		//当left <= right 时合法
		while(left <= right){
			int mid = (left + right) / 2;
			//左侧区域查找
			if(toFind < arr[mid]){
				right = mid - 1;
			}
			//右侧区域查找
			else if(toFind > arr[mid]){
				left = mid + 1;
			}
			//找到值并返回
			else{
				return mid;
			}
		}
		//没找到时，返回-1
		return -1;
	}
} 

测试数据：toFind = 6;
下标为5；
结果如下：