异常处理

Question

I want it allow the user to enter in two int after the incorrect input. I tried continue; in the catch block, but it only threw run-time errors. I just want it to go back to the top of the main method after the throwing the error. See how in the pic it didn't allow the user to input any numbers. I want to fix that part.

Here's the code. This is only for practice.

/**
practing exceptions, example 1 in book for exceptions 
*/ 

    import java.util.Scanner;

    public class PracticeExceptions extends Exception {

    public static void main(String[] args)
    {
     String response = "y";
     Scanner keyboard = new Scanner(System.in);

     do{ 
     int n1, n2;
     double r;
     System.out.println("Please enter two numbers");

     try{
            n1 = keyboard.nextInt();
            n2 = keyboard.nextInt();
            r = (double) n1/n2;     

        System.out.format("Your answer: %.2f %n", r);

       }catch(Exception a){

       System.out.println("Invaild input please try again");

       }

       System.out.println("Again (y/n)");
       response = keyboard.next();

       }while(response.equalsIgnoreCase("y"));
     }
   }

Answer 1

Get rid of the invalid input in you scanner buffer

 }catch(Exception a){
    System.out.println("Invalid input please try again");
    keyboard.next();
 }

The code will now drop down to System.out.println("Again (y/n)");

If you want to loop back to the top add a continue after keyboard.next();