Is there a way to accept a single character as an input?-CodePudding

New to programming, so my apologies if this is dumb question.

When utilizing the Scanner class, I fail to see if there is an option for obtaining a single character as input. For example,

import java.util.Scanner;
public class Test {
    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);
        String a = input.nextLine();
    }
}

The above code allows me to pull the next line into a string, which can then be validated by using a while or if statement using a.length() != 1 and then stored into a character if needed.

But is there a way to pull a single character instead of utilizing a string and then validating? If not, can someone explain why this is not allowed? I think it may be due to classes or objects vs primitive types, but am unsure.

CodePudding user response：

You can use System.in.read() instead of Scanner

char input = (char) System.in.read();

You can also use Scanner, doing something like:

Scanner scanner = new Scanner(System.in);
char input = scanner.next().charAt(0);

For using Stringinstead of char, I prefer to convert to String, since using regex, like the one used in the answer that specifies a delimiter, can make the code less readable:

Scanner scanner = new Scanner(System.in);
String input = String.valueOf(input.next().charAt(0));

This is less fancy than:

new Scanner(System.in).useDelimiter("(?<=.)");

But I guess that for a newbie, it'll be easier to understand any of my proposals.

CodePudding user response：

Set the delimiter so every character is a token:

Scanner input = new Scanner(System.in).useDelimiter("(?<=.)");
String c = input.next(); // one char

The regex (?<=.) is a look behind, which has zero width, that matches after every character.