question regarding exceptions..

[SCS17]

Hey,

This might be a very simple question.
I'm writing a simple program where the user is asked to enter an integer.

System.out.println("Please enter an integer");
a = scanner.nextInt();

So i'm expecting him to enter an integer, but lets say that the user didnt enter an integer instead he entered a word or anything other than an int. I need to print him a message saying "Sorry... you have to enter an integer.." and then reprompt him again to enter an integer "Please enter an integer". Basically what should i do ???

Should I write an "if statement" or should i try to catch the exception ???
I hope somebody can clarify this point.. maybe with an example.

Any help would be appreciated. Thanks alot.


Heres the code:


public class DemoProgram2{


public static void main(String[] args){


Scanner scanner;

int x; //raw date information

//create scanner for reading user keyboard input
scanner = new Scanner(System.in);

//read and int representation of the date from the keyboard
System.out.print("Enter birthday as an DDMMYYYY int and [ENTER]: ");
x = scanner.nextInt();

//output the data collected
System.out.println("Your Data");
System.out.println("=========");
System.out.println("x=" + x);
System.out.println("Your Birthday");


int day = (x - x % 1000000) / 1000000;
int month = (x%1000000 - x % 10000)/10000;
int year = x % 10000;
System.out.println(day + "/" + month + "/" + year);

}


}

[hardwired]

Code:

import java.util.Scanner;

public class DP2 {
    public static void main(String[] args) {
        //create scanner for reading user keyboard input
        Scanner scanner = new Scanner(System.in);
        String line;
        do {
            //read and int representation of the date from the keyboard
            System.out.print("Enter birthday as an DDMMYYYY int and [ENTER]: ");
            line = scanner.nextLine();
        } while(!process(line));
        scanner.close();
    }

    private static boolean process(String s) {
        char[] chars = s.toCharArray();
        if(chars.length != 8)
            return false;
        for(int j = 0; j < chars.length; j++) {
            if(!Character.isDigit(chars[j]))
                return false;
        }
        int x = Integer.parseInt(s);
        //output the data collected
        System.out.println("Your Data");
        System.out.println("=========");
        System.out.println("x=" + x);
        System.out.println("Your Birthday");

        int day = (x - x % 1000000) / 1000000;
        int month = (x%1000000 - x % 10000)/10000;
        int year = x % 10000;
        System.out.println(day + "/" + month + "/" + year);
        return true;
    }
}

[SCS17]

Thanks alot for your help.
Do you know where should I add the

System.out.println("Sorry, thats not acceptable.. enter an int");

Thanks again.. really appreciate it.

[hardwired]

Code:

String line;
boolean okay = true;
do {
    if(!okay)
        System.out.println("Sorry, thats not acceptable.. enter an int");
    System.out.print("Enter birthday as an DDMMYYYY int and [ENTER]: ");
    line = scanner.nextLine();
} while(!(okay = process(line)));