课堂练习

package com.yingyong.day13;

public class MiddleFind {

public static void main(String[] args) {
	// TODO Auto-generated method stub
	int [] arr3 = new int[] {-99,-54,-2,0,2,33,43,256,999};
	boolean isFlag = true;
	int number = 256;  //int number = 25；
	int head = 0;  //首索引位置
	int end = arr3.length - 1;  //尾索引位置
	while(head <= end) {
		int middle = (head + end) / 2;
		if(arr3[middle] == number) {
			System.out.println("找到指定元素，索引为：" + middle);
			isFlag = false;
			break;
		}else if(arr3[middle] > number) {
			end = middle - 1;
		}else {//arr3[middle] + number
			head = middle + 1;
		}
				
		
	}
	if(isFlag) {
		System.out.println("未找到指定元素");
	}

}

} 结果：找到指定元素，索引为：7