二分法

import java.util.Scanner;


/**
 * @author Rory
 *@category 二分法查找
 */
public class erfen {


public static void main(String[] args) {
int[]a=new int[]{1,23,56,78,99,102,456,789,999};
System.out.println("请输入你猜的数字");
Scanner sc=new Scanner(System.in);
int s=sc.nextInt();
int min=0,max=a.length-1;
while(min<=max){
int middle=(min+max)/2;
if(s==a[middle]){
System.out.println("找到了，下标是："+middle);
System.exit(0);
}
if(s<a[middle]){
max=middle-1;
}else{
min=middle+1;
}
}
System.out.println("没有找到");
}


}