使用文件编号计算 GCM - NoSuchElementException

Question

我正在尝试将这些数字存入文件并相应地计算 GCM。但是我一直收到 NoSuchElementException。

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

public class Prog280a {

public static void main(String[] args) {
    Scanner in = null;
    int greater = 1;
    int lesser = 1;
    int a = 1;
    int b = 1;
    int originalA = 0;
    int originalB = 0;

    try {
        in = new Scanner(new File(("C:\Users\####\Desktop\####\Eclipse\#######\#######2\src\Prog280a.dat")));
    } catch (FileNotFoundException e) {
        System.out.println("File is not found try again.");
        System.exit(0);
    }

    while (in.hasNextInt()) {
        while (a != 0) {
            greater = in.nextInt();
            lesser = in.nextInt();
            if (greater > lesser) {a = greater; b = lesser;} else {b = greater; a = lesser;}
            originalA = a;
            originalB = b;
            a = a - b;
        }
        System.out.println("The GCD of " + originalA + " & " + originalB + " is " + b);
        a = 1;
        b = 1;
    }

}

}

好的，在我说的那一行。 'greater = in.nextInt();'系统说没有这样的元素异常。为什么要这样做？请帮忙

内容如下：

Exception in thread "main" java.util.NoSuchElementException
at java.util.Scanner.throwFor(Unknown Source)
at java.util.Scanner.next(Unknown Source)
at java.util.Scanner.nextInt(Unknown Source)
at java.util.Scanner.nextInt(Unknown Source)
at Prog280a.main(Prog280a.java:25)

顺便说一下，这些是文件中的数字： 25 10 81 41 255 138 847 624 84 420 182 637 620 420 36 24 75 125 1 17

Answer 1

我的假设是否正确，您不一定会在调用第一个 greater = in.nextInt() 时出错？

因为我认为你的问题出在循环上。在你的外循环中，你正确地询问了 in.hasNext() - 但是，在你的内循环中，你似乎在循环 a != 0 - 所以，你可以继续调用 greater = in.nextInt(); lesser = in.nextInt(); 而没有检查你的枚举是否有更多元素。

Answer 2

将你内心的 while 更改为 if。第一个 while 正在创建一个连续循环，直到到达文件末尾。

Scanner in = null;
int greater = 1;
int lesser = 1;
int a = 1;
int b = 1;
int originalA = 0;
int originalB = 0;

try {
    in = new Scanner(new File(("C:\Users\####\Desktop\####\Eclipse\#######\#######2\src\Prog280a.dat")));
} catch (FileNotFoundException e) {
    System.out.println("File is not found try again.");
    System.exit(0);
}

while (in.hasNextInt()) {
    if (a != 0) {
        greater = in.nextInt();
        lesser = in.nextInt();
        if (greater > lesser) {a = greater; b = lesser;} else {b = greater; a = lesser;}
        originalA = a;
        originalB = b;
        a = a - b;
    }
    System.out.println("The GCD of " + originalA + " & " + originalB + " is " + b);
    a = 1;
    b = 1;
}

使用文件编号计算 GCM - NoSuchElementException

Calculating GCM Using File Numbers - NoSuchElementException

java

eclipse

java.util.scanner

nosuchelementexception