Wanting input to be String value only

[Kevin O'Sullivan]

Hi
If you want user input to be strings only and you want to catch  any integers entered by the user, how do you do it?I want the user to enter string values only and to catch any integers entered, when I input integers its doesn't display the error message.

import java.util.Scanner;
import java.util.InputMismatchException;
public class Country{

	public static void main(String[]args){


		boolean isValid = true;
		String Country1 = "Ireland";
		String Country2 = "England";
		String Country3 = "France";

		countryOfOrigin(isValid,Country1,Country2,Country3);
	}

	public static void countryOfOrigin(boolean isValid,String Country1,String Country2,String Country3){

      Scanner sc = new Scanner(System.in);
      do{
         try{
	  		System.out.println("Please enter your country of origins: ");
	  	    String Country = sc.nextLine();
	  	    if(Country.equals("Ireland") || Country.equals("England") || Country.equals("France")){
	  	       System.out.println("Thank");
	  	       isValid = true;
	  	    }
	  	    else{
	  	    	System.out.println("Wrong,please enter another country again: ");
	  	    	isValid = false;
	  	    }
	  	}
	  	catch(InputMismatchException e)
	  	{
	  		System.out.println("Please enter strings only!");
	  	}
	  }while(!isValid);
	}

Thanks

[Campbell Ritchie]

The input to the command line/standard input stream is always in text format. Everything you pass into it is a String. You cannot get a number from the standard input stream, you can only take the input and parse it as a number. Which you are not doing. Any text counts as a valid String, even the empty (0‑length) String. There is no built‑in way to test that text constitutes a word in English. You can try testing the input to see whether it is a number. Pass the text to a Scanner constructor and try its hasNextXXX() methods. Or you can try a regular expression to test for letters. Neither approach is really good however.

[Grzegorz Kędzior]

Try this. But remember return string value can contain a numbers i.e. "1an3z".

public String pureNumberOrString(String str) {
	if (str.matches("\\d+")) {
		return "number";
	} else {
		return "string = " + str;
	}
}

The second way is to use static method paseInt() which throw exception if the string does not contain a parsable integer.

[Zach Rode]

Couple of questions that might help. Why do you not want any numbers? If you are trying to validate data to make sure its a country "asdfjkansdfjansdfajdfna" is just as bad as "Ireland99".

Second, I feel this might be a really good situation to use an enum for country names as the countries you are looking for are static. Just a thought.

-Zach

[Campbell Ritchie]

Grzegorz Kędzior wrote:. . . static method paseInt() which throw exception if the string does not contain a parsable integer.

Please consider whether that really is a good use for exceptions.

You misspelt the method name: it is Integer#parseInt(...)