使用断言检查值是否在范围内。

import java.util.Scanner;


public class Main

{/*来自 N o w J a v a . c o m*/

   public static void main(String[] args)

   {

      Scanner input = new Scanner(System.in);

      

      System.out.print("Enter a number between 0 and 10: ");

      int number = input.nextInt();

      

      // assert that the value is >= 0 and <= 10

      assert (number >= 0 && number <= 10) : "bad number: " + number;

      

      System.out.printf("You entered %d%n", number);

   } 

}