java.util.NoSuchElementException: No line found at java.base/java.util.Scanner.nextLine(Scanner.java:1651)

Question

Code:

import java.util.Scanner;

public class SchleifenUebung {
    public void zeilenAusgeben(int Zeilenanzahl) {
        int index = 1;
        while (Zeilenanzahl >= 0) {
            System.out.println("Zeile z" + index);
            index++;
        }
    }

    public void ausgabeQuadratZahlen() {
        System.out.println("Eingabe Grenze:");
        Scanner scanner = new Scanner(System.in);
        String line;
        int n;
        int index = 1;
        do {
            System.out.println("Eingabe Grenze:");
            line = scanner.nextLine();
            n = Integer.parseInt(line);
            index++;
        } while (n >= 1 && n <= 100);

        while (index <= n) {
            System.out.println(n + "^2=" + index * index);
            index++;
        }
    }
}

Exception:

java.util.NoSuchElementException: No line found at java.base/java.util.Scanner.nextLine(Scanner.java:1651)

Answer 1

Apparently you try to scan input until a number between 1 and 100 is entered, but with while(n >=1 && n <=100) you do the opposite, and if no number outside that range appears before the end of the input stream, the shown exception arises. Change to while (n < 1 || 100 < n) .

Answer 2

您可以使用，Scanner 正在证明可以将 Inputs 直接转换为 int 的方法，它可以从您身边进行解析，您不必手动进行

  scanner.nextInt();