帮我看看二分法查找的问题

Question

public class Search
{
    public static void  main(String args[]) throws java.io.IOException
 {
    int arry[]={9,10,3,5,7,2,1,8,4};
    int i;
    int j;
    int temp;
    for(i=0;i<arry.length;i++)
      for(j=i+1;j<arry.length;j++)
         {
           if(arry[i]>arry[j])
            {
                 
              temp=arry[i];
              
              arry[i]=arry[j];
              arry[j]=temp;
             }
          }
       System.out.println("输出排序后的数组\n");
       for(i=0;i<arry.length;i++)
         System.out.println(arry[i]+",");      boolean flag=false;
     
     int left=0;
     int right=arry.length-1;
     System.out.println("请输入要查询的数\n");
     int a=System.in.read();
  
    
        while(left<=right)
         {
           int mid=(left+right)/2;
           if(arry[mid]==a)
             { 
               flag=true;
               break;
             }
           else if(arry[mid]>a)
             {
               right=mid-1;
             }
           else
             {
               left=mid+1;
             }  
         }
        if(flag==true)
           {
              System.out.println("找到"); 
           }
           
        else
          {
              System.out.println("没找到"); 
          }      
}
}
数组里有数也说没找到　帮我看看谢谢

Answer 1

int a=System.in.read() - '0';

Answer 2

读进来的虽说是int,但其实是char

Answer 3

这个System.in.read()我到现在也不知道它是怎么个用法，明白的大虾讲一下吧。