放 keyboard.nextLine（）在这一行之后：

int answer=keyboard.nextInt();

当您使用 nextLine（）时，这是一个常见问题/ code> nextInt（） 扫描程序类的方法之后的方法。

This is a common problem that usually happens when you use nextLine() method after nextInt() method of Scanner class.

实际发生的情况是，当用户在 int answer = keyboard.nextInt（）; 中输入一个整数时，扫描仪将仅采用数字和保留换行符 \ n 。所以你需要通过调用 keyboard.nextLine（）; 来放弃那个新行字符，然后你可以调用 String input = keyboard.nextLine（）; 没有任何问题。

What actually happens is that when the user enters an integer at int answer = keyboard.nextInt();, the scanner will take the digits only and leave the new-line character \n. So you need to do a trick by calling keyboard.nextLine(); just to discard that new-line character and then you can call String input = keyboard.nextLine(); without any problem.