java - Max()方法使用来自用户Java的输入列表

Question

enter image description here一旦我进入列表。它不会显示最大值。我尝试在最后一个 println 中调用 max ，但仍然不起作用。

 ArrayList<Double> numbers = new ArrayList<Double>();

      Scanner keyboard = new Scanner(System.in);
      System.out.println("Please enter a list of numbers: ");

      while (keyboard.hasNextDouble())
      {
         double input = keyboard.nextDouble();
         numbers.add(input);      
      }
    Double max = Collections.max(numbers);
        System.out.println("The Maximum is: "  );

}} 

Answer 1

怎么样

编辑

// check to make sure that numbers has some elements

if (numbers.size () <= 0) {
   // some message
   return;
}
Double max = Collections.max(numbers);
System.out.println("The Maximum is: "  + max );
//                                     ^^^^^^