在GetArray方法中，生成的数组始终为空

发布于 2025-01-24 10:24:07 字数 876 浏览 0 评论 0原文

public static void main(String[] args) throws FileNotFoundxception {
    File usdCoins = new File("C:\\Users\\saif9\\OneDrive\\Desktop\\USD coins.txt");
    getArray(usdCoins);
}

public static void getArray (File coins) {
    try {
        Scanner reader = new Scanner(coins);
        int counter = 0;
        while (reader.hasNextDouble()) {
             System.out.print(reader.nextDouble() + " / ");
             System.out.println(counter);
             counter++;
        }

        double jodCoins[] = new double[counter];
        int i = 0;
        while (reader.hasNextDouble()) {
             jodCoins [i] = reader.nextDouble();
             i++;
             for (int j= 0; j < i; j++) {
                 System.out.println(jodCoins[j]);
             } 
        }
    }
    catch (Exception e) {
        // ????
    }

原文

public static void main(String[] args) throws FileNotFoundxception {
    File usdCoins = new File("C:\\Users\\saif9\\OneDrive\\Desktop\\USD coins.txt");
    getArray(usdCoins);
}

public static void getArray (File coins) {
    try {
        Scanner reader = new Scanner(coins);
        int counter = 0;
        while (reader.hasNextDouble()) {
             System.out.print(reader.nextDouble() + " / ");
             System.out.println(counter);
             counter++;
        }

        double jodCoins[] = new double[counter];
        int i = 0;
        while (reader.hasNextDouble()) {
             jodCoins [i] = reader.nextDouble();
             i++;
             for (int j= 0; j < i; j++) {
                 System.out.println(jodCoins[j]);
             } 
        }
    }
    catch (Exception e) {
        // ????
    }

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青衫儰鉨ミ守葔 2025-01-31 10:24:07

您应该在第一个时间之后重新调整读者，读者没有更多的读数要读取，因此您需要再次将其分配给新的扫描仪（如果您需要重复使用Coins文件的相同数据，则在此处尚不清楚。）：

public static void main(String[] args) throws FileNotFoundxception {
    File usdCoins = new File("C:\\Users\\saif9\\OneDrive\\Desktop\\USD coins.txt");
    getArray(usdCoins);
}

public static void getArray (File coins) {
    try {
        Scanner reader = new Scanner(coins);
        int counter = 0;
        while (reader.hasNextDouble()) {
             System.out.print(reader.nextDouble() + " / ");
             System.out.println(counter);
             counter++;
        }

        double jodCoins[] = new double[counter];
        int i = 0;

        // re-initialise the reader here :
        reader = new Scanner(coins);

        while (reader.hasNextDouble()) {
             jodCoins [i] = reader.nextDouble();
             i++;
             for (int j= 0; j < i; j++) {
                 System.out.println(jodCoins[j]);
             } 
        }
    }
    catch (Exception e) {
        // ????
    }

You should re-initialise the reader ,after the first while , the reader dont have more double to read , so you need to assign it again to a new Scanner (entries are not clear here if you need to reuse the same data of coins file ) :

public static void main(String[] args) throws FileNotFoundxception {
    File usdCoins = new File("C:\\Users\\saif9\\OneDrive\\Desktop\\USD coins.txt");
    getArray(usdCoins);
}

public static void getArray (File coins) {
    try {
        Scanner reader = new Scanner(coins);
        int counter = 0;
        while (reader.hasNextDouble()) {
             System.out.print(reader.nextDouble() + " / ");
             System.out.println(counter);
             counter++;
        }

        double jodCoins[] = new double[counter];
        int i = 0;

        // re-initialise the reader here :
        reader = new Scanner(coins);

        while (reader.hasNextDouble()) {
             jodCoins [i] = reader.nextDouble();
             i++;
             for (int j= 0; j < i; j++) {
                 System.out.println(jodCoins[j]);
             } 
        }
    }
    catch (Exception e) {
        // ????
    }

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