如何在循环时停止文件结束指示符？

Question

package studenttest;

import java.util.Scanner;

public class StudentTest {

public static void main(String[] args) {

   Scanner input = new Scanner(System.in);

   int total=0;
   int gradeCounter=0;
   int aCount=0;
   int bCount=0;
   int cCount=0;
   int dCount=0;
   int fCount=0;

   System.out.printf("%s%n%s%n %s%n","Enter the integer grades in the range 
   0-100.","Type the end-of-file indicator to terminate input:","On 
   Unix/Linux/Mac OS X type <Ctrl> d then press Enter On Windows type <Ctrl> 
   z then press Enter");

   while(input.hasNext()){

       int grade = input.nextInt();
       total += grade;
       ++gradeCounter;

       switch(grade/10){

           case 9:
           case 10:
               ++aCount;
               break;
           case 8:
               ++bCount;
               break;
           case 7:
               ++cCount;
               break;
           case 6:
               ++dCount;
               break;
           default:
               ++fCount;
               break;
       }   
   }

   System.out.println("Grade Report: ");

   if(gradeCounter != 0){

       double average = (double)total/gradeCounter;

       System.out.printf("Total of the %d grades entered is %d%n", 
       gradeCounter,total);
       System.out.printf("Class average is %f%n", average);

       System.out.printf("%n%s%n%s%d%n%s%d%n%s%d%n%s%d%n%s%d%n","Number of 
       Students who received each grade: 
       ","A",aCount,"B",bCount,"C",cCount,"D",dCount,"F",fCount);
   }
   else
   System.out.println("No Grades were entered");

   }

}

如何停止此循环？ 我目前在Windows操作系统上，确切地说是Windows 10。我尝试使用Ctrl Z来关闭输入输入+输入的过程，但是没有工作。如果你想知道我正在使用NetBeans！