CODEWITHSUNDEEP
javajava.util.scannerrestriction
Potato Salad
Potato Salad

Reputation: 37

How to restrict user scanner input data type (java)?

say, I want the user to input an integer only but not something like "bacon", is there a way to restrict user input to integers(or other data types) so I don't get any errors and or inputs other than an integer?

Upvotes: 1

Views: 6005

Answers (2)

james
james

Reputation: 1687

Here is a fully functional example:

import java.util.Scanner;

public class Temp {

    public static void main(String[] args) {
        Scanner inp = new Scanner(System.in);
        int num = 0;
        String input = "";
        String exit = "exit";
        boolean isStringNumber = true;//If the String is not Number

        System.out.println("NOTE: To exit, type the word exit and press enter key");

        while(true){

            System.out.println("\nPlease enter a number only...");
            input = inp.nextLine();

            if(input.equalsIgnoreCase(exit)){break;}

            isStringNumber = input.matches("[0-9]+");//Check if no digits in string

            if(isStringNumber == false){
                System.out.println("\nYou entered a non number " + input);
                System.out.println("Remove all non numbers from your input and try again !");
                continue;
            }else{
                num = Integer.parseInt(input);
                System.out.println("You entered " + num);
            }

        }

        System.out.println("Exiting program...");

    }

}

Upvotes: 1

mrwntrk
mrwntrk

Reputation: 46

Assuming your Scanner has the name myScanner:

public static int checkMyInput () { 
    try {
        return myScanner.nextInt();
    } catch (InputMismatchException e ) {
         myScanner.next();
         System.out.println("bacon luff");
        return 0 ;
    }
}

and then you can call that method.

Upvotes: 3

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