Základní kalkulačka – Java – Fórum – Programujte.com

Ahoj,

Chci se zeptat, jak mám udělat to, že jestli odpověď uživatele není číslo, tak mu to napíše "invalid input" a a dá mu to znovu?

zde kód:

import java.util.Scanner;

public class Main {

    public static void main (String[] args) {
        Scanner nevim = new Scanner(System.in);
        int a;
        int b;
        int sum;




        System.out.print("Write first number, please: ");
        a = nevim.nextInt();
        System.out.print("Write second number, please: ");
        b = nevim.nextInt();
        sum = a + b;
        System.out.println("The answer is " + sum);
    }
}

#1 Boom
Zkus to třeba takhle

import java.util.Scanner;

public class Calc {

    public static void main (String[] args) {
        int a = readInt("Write first number, please: ");
        int b = readInt("Write second number, please: ");
        int sum = a + b;
        System.out.println("The answer is " + sum);
    }

    private static int readInt(String prompt) {
        while (true) {
            Scanner input = new Scanner(System.in);
            try {
                System.out.print(prompt);
                int a = input.nextInt();
                return a;
            } catch (java.util.InputMismatchException e) {
            }
        }
    }

}