java 动态读写二维数组

Java中的二维数组可以用以下方式动态读写：

1. 初始化二维数组

int[][] array = new int[row][column];

其中，row是行数，column是列数。

2. 读取二维数组中的值

int value = array[rowIndex][columnIndex];

其中，rowIndex是行索引，columnIndex是列索引。

3. 修改二维数组中的值

array[rowIndex][columnIndex] = newValue;

其中，rowIndex是行索引，columnIndex是列索引，newValue是要修改的新值。

示例代码：

int[][] array = new int[2][3]; // 初始化二维数组

// 读取二维数组中的值
int value = array[1][2];

// 修改二维数组中的值
array[1][2] = 10;

相关问题

java 动态二维数组文件读写

1. 文件读取

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

public class Dynamic2DArrayFileReader {
    public static void main(String[] args) {
        try {
            File file = new File("input.txt");
            Scanner scanner = new Scanner(file);

            // Read the number of rows and columns
            int rows = scanner.nextInt();
            int cols = scanner.nextInt();

            // Initialize the 2D array
            int[][] array = new int[rows][cols];

            // Read the elements of the array
            for (int i = 0; i < rows; i++) {
                for (int j = 0; j < cols; j++) {
                    array[i][j] = scanner.nextInt();
                }
            }

            // Print the array
            for (int i = 0; i < rows; i++) {
                for (int j = 0; j < cols; j++) {
                    System.out.print(array[i][j] + " ");
                }
                System.out.println();
            }

            scanner.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }
}

2. 文件写入

import java.io.File;
import java.io.FileNotFoundException;
import java.io.PrintWriter;

public class Dynamic2DArrayFileWriter {
    public static void main(String[] args) {
        int[][] array = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};

        try {
            File file = new File("output.txt");
            PrintWriter writer = new PrintWriter(file);

            // Write the number of rows and columns
            writer.println(array.length);
            writer.println(array[0].length);

            // Write the elements of the array
            for (int i = 0; i < array.length; i++) {
                for (int j = 0; j < array[0].length; j++) {
                    writer.print(array[i][j] + " ");
                }
                writer.println();
            }

            writer.close();
        } catch (FileNotFoundException e) {
            e.printStackTrace();
        }
    }
}

java 二维数组文件读写

Java 二维数组可以通过文件读写来进行操作。

文件读取：

import java.io.*;

public class ReadFile {
    public static void main(String[] args) {
        try {
            File file = new File("filename.txt");
            BufferedReader br = new BufferedReader(new FileReader(file));
            String line;
            int[][] arr = new int[3][3];
            int i = 0;
            while ((line = br.readLine()) != null) {
                String[] values = line.split(",");
                for (int j = 0; j < values.length; j++) {
                    arr[i][j] = Integer.parseInt(values[j]);
                }
                i++;
            }
            br.close();
            for (int[] row : arr) {
                for (int value : row) {
                    System.out.print(value + " ");
                }
                System.out.println();
            }
        } catch (IOException e) {
            System.out.println("Error reading file");
            e.printStackTrace();
        }
    }
}

文件写入：

import java.io.*;

public class WriteFile {
    public static void main(String[] args) {
        try {
            int[][] arr = {{1, 2, 3}, {4, 5, 6}, {7, 8, 9}};
            BufferedWriter bw = new BufferedWriter(new FileWriter("filename.txt"));
            for (int[] row : arr) {
                for (int value : row) {
                    bw.write(value + ",");
                }
                bw.newLine();
            }
            bw.close();
            System.out.println("File written successfully");
        } catch (IOException e) {
            System.out.println("Error writing to file");
            e.printStackTrace();
        }
    }
}