我正在尝试使用带有 .charAt() 的 Scanner 从单个字符串获取字符输入

Question

im trying to make a dice roller that can take a single input and roll a die with a certain number of sides a certain number of times. so if I input "2d4" itll roll a 4 sided die 2 times, and give me both results separately. To do this ive been trying to use the scanner class since im rather new to programming. Im trying to take it step by step and use what I know. Im sure there are better classes to use and such but Im trying to do it with scanner specifically.

import java.util.Scanner;
import java.util.Random;
public class DiceRoller3 {
    public static void main(String[] args) {

        Scanner input = new Scanner(System.in);
        Random Random = new Random();

        char NumberOfDice = input.next().charAt(0);

        char DieType = input.next().charAt(2);

This, i believe is causing me to have to create two inputs, due to it searching for the "next" input to look for a character in. I would like to be able to do it with one input, is there a way to do that?

Answer 1

You can use the nextLine method of Scanner class

String userInput = input.nextLine();
char noOfDie = userInput.charAt(0);
char dieType = userInput.charAt(2);

The method returns a string of a complete line entered by the user. Works by giving your input and pressing enter.

Answer 2

Try this Scanner input = new Scanner(System.in); Random Random = new Random();

    String inputString = input.next();
    char numberOfDice = inputString.charAt(0);
    char dieType = inputString.charAt(2);

Please mind each time you call next() for scanner you read next String value from input stream. It is of course up to you how to input your data but you could also enter it separately, ie

2
d
4

instead of

2d4

in that case you would read it like this:

    char numberOfDice = input.next().charAt(0);
    char die = input.next().charAt(0);
    char dieType = input.next().charAt(0);

Answer 3

I'm not a java guy but if the format is always number d number you can do this

 Scanner input = new Scanner(System.in);
 String myinput= input.nextLine();
 int NumberOfDice=Character.getNumericValue(myinput.charAt(0));
 int DieType= Character.getNumericValue(myinput.charAt(2));

EDIT: this is better if the your dice number can go above 9

 int NumberOfDice=Integer.parseInt(myinput.substring(0,String.IndexOf("d")));
 int DieType =Integer.parseInt(myinput.substring(String.IndexOf("d")+1)));

Answer 4

You may want to get the whole string at once, locate the position of d , then get the left and the right part of it :

    Scanner input = new Scanner(System.in);

    String string = input.nextLine();

    int indexOfD = string.indexOf('d');

    String numberOfDice = string.substring(0, indexOfD);
    String dieType = string.substring(indexOfD + 1, string.length());

    System.out.println(numberOfDice);
    System.out.println(dieType);

Alternatively, you may also split the string with d as the separator :

    String[] parts = string.split("d");

    String numberOfDice = parts[0];
    String dieType = parts[1];