import java.util.Scanner;


public class ReadInt
{
    public static void main(String[] args)
    {
        Scanner input = new Scanner(System.in);
        
        System.out.println("Please enter a number.");
        
        int number=0;
        
        //! = is not. So if input doesn't have a next int, the condition is true
        /*
         if(!input.hasNextInt())
         {
         System.out.println("The entered number was not an integer");
         }
         else
         {
         number = input.nextInt();
         System.out.printf("You typed: %d \n", number); 
         }
         */ 
        
        while(!input.hasNextInt())
        {
            System.out.println("That was not a number. Please enter a number.");
            input.nextLine(); //throw away whatever they typed. We know it is not an integer.
        }
        
        //We know the user has put in an integer
        number = input.nextInt();
        System.out.printf("You typed: %d \n", number);
        
    }
}