Question

我有一个名为＆＃34; input.txt＆＃34;以下是数字。我想读取这个文件并将其变成一个数组。第一个整数 - 10表示数组中索引或元素的数量，因此有10个点。下面的代码是我到目前为止所做的，我只是不知道如何从第一行读取input.txt

此数组的大小将是文件中的第一个数字

static void display(int[] numArray) {
    System.out.println("Array contents: ");
    for (int i = 0; i < numArray.length; i++) {
        System.out.print(numArray[i] + " ");
    }
    System.out.println();
}

public static void main(String[] args) {

    Scanner input = new Scanner(System.in);

    int[] numberArray = new int[10];

    System.out.println("Enter the name of your file (including file extension): ");
    String filename = input.next();

    int count = 0;

    try {

        Scanner in = new Scanner(new File(filename));
        int result = in.nextInt();

        while (in.hasNextInt()&& count < 10) {
            numberArray[count] = result;
            count = count + 1;
            result = in.nextInt();
        }
    } catch (FileNotFoundException e) {
        System.out.println("That file was not found. Program terminating...");
        e.printStackTrace();
    }

    display(numberArray);

}

Answer 1

这样的事情应该有效（未经测试）。注意如何首先抓取大小，基于该大小创建的数组，然后正在读取文件的其余部分。

static void display(int[] numArray) {
    System.out.println("Array contents: ");
    for (int i = 0; i < numArray.length; i++) {
        System.out.print(numArray[i] + " ");
    }
    System.out.println();
}

public static void main(String[] args) {
    Scanner input = new Scanner(System.in);
    System.out.println("Enter the name of your file (including file extension): ");
    String filename = input.next();

    int count = 0;
    int[] numberArray;
    try {
        Scanner in = new Scanner(new File(filename));
        int size= in.nextInt();
        numberArray = new int[size];
        int result;
        while (in.hasNextInt()&& count < size) {
            numberArray[count] = result;
            count = count + 1;
            result = in.nextInt();
        }
    } catch (FileNotFoundException e) {
         System.out.println("That file was not found. Program terminating...");
        e.printStackTrace();
    }
    display(numberArray);
}

Answer 2

您需要创建第一行大小的数组，如果需要，可以放入数组。您可以尝试以下方式：

如果您使用的是Java 7或更高版本，可以尝试以下方法：

public static void main(String[] args) {
    try (final Scanner input = new Scanner(System.in)) {
        final int[] numberArray = new int[10];

        System.out.println("Enter the name of your file (including file extension): ");
        final String filename = input.next();

        try (final Scanner in = new Scanner(new File(filename))) {
            final int count = in.nextInt();
            for (int i = 0; in.hasNextInt() && i < count; i++) {
                numberArray[i] = in.nextInt();
            }
            display(numberArray);
        } catch (final FileNotFoundException e) {
            System.out.println("That file was not found. Program terminating...");
            e.printStackTrace();
        }
    }
}

如果你在7之前使用java，试试这个：

public static void main(String[] args) {
    try (final Scanner input = new Scanner(System.in)) {

        System.out.println("Enter the name of your file (including file extension): ");
        final String filename = input.next();

        int[] numberArray = null;
        try (final Scanner in = new Scanner(new File(filename))) {
            final int count = in.nextInt();

            numberArray = new int[count];

            for (int i = 0; in.hasNextInt() && i < count; i++) {
                numberArray[i] = in.nextInt();
            }
            display(numberArray);
        } catch (final FileNotFoundException e) {
            System.out.println("That file was not found. Program terminating...");
            e.printStackTrace();
        }
    }
}

如果要将第一行添加到数组中，请将numberArray[0] = count;放在numberArray = new int[count];下方并使用 1 初始化步骤。

将文件中的数字存储到数组中

2 个答案: