java应用程序中判断用户输入的一个整数是否在已知数组里。

import java.util.*;

class Example2_5 {

   public static void main(String args[]) {

      int start=0,end,middle;

      int a[] = {12,45,67,89,123,-45,67};

      int N = a.length;

      for(int i=0; i<N; i++) {     //选择法排序数组

     for(int j = i+1; j < N;j++){

           if(a[j] < a[i]){

             int t = a[j];

             a[j] = a[i];

             a[i] = t;

           }

         }

      }

      System.out.println(Arrays. toString(a));

      Scanner scanner = new Scanner(System.in);

      System.out.println("输入整数，程序判断该整数是否在数组中:");

      int number = scanner.nextInt();

      int count =0 ;

      end = N;

      middle=(start+end)/2;

      while(number!=a[middle]){

           if(number>a[middle])

              start=middle;

           else if(number<a[middle])

              end=middle;

           middle=(start+end)/2;

           count++;

          if(count>N/2)

             break;

      }

      if(count>N/2)

         System.out.printf("%d不在数组中.\n",number);

      else

         System.out.printf("%d在数组中.\n",number);

   }

}