Java - 不兼容的类型：boolean不能转换为int

Question

import java.util.Scanner;
import java.lang.Object;

public class Game {
    public static void main(String[] args) {
        int numberOfRounds = -1; 

        while (numberOfRounds <= -1) { 
            Scanner reader = new Scanner(System.in);
            System.out.print("Please input the number of rounds. The number of rounds must be greater than or equal to 0: ");
            numberOfRounds = reader.hasNextInt();
            reader.close();
        }
        System.out.println("number is" + numberOfRounds);
    }
}

I've been trying to get the user to input a number of rounds. But the rounds have to be greater than or equal to 0, because negative numbers do not work. Any help?

Error code below:

Game.java:11: error: incompatible types: boolean cannot be converted to int
                    numberOfRounds = reader.hasNextInt();
                                                      ^
1 error

Answer 1

Instead of using reader.hasNextInt(); you should use reader.nextInt();

But remember that this method throws 3 types of errors which should be handled:

• InputMismatchException - if the next token does not match the Integer regular expression, or is out of range
• NoSuchElementException - if input is exhausted
• IllegalStateException - if this scanner is closed