Question

我遇到的问题是2D数组没有打印出数组中的所有内容，当我运行evolve方法时，它不会像第一次那样打印出2D数组。想知道什么是错误使它不打印出整个数组，而不是在evolve方法运行时以相同的方式打印数组？阵列中的每个打印件都需要在25x75网格中

所需的初步结果：

实际结果：

进化方法结果：项目4：

import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.util.Arrays;
import java.util.Scanner;

public class Project4 {

    public static void main(String[] args) throws IOException {
        Scanner input = new Scanner(System.in); // Created a scanner
        System.out.println("Enter the file name you would like to use");
        File file = new File(input.nextLine()); // Takes file name to find file
        Scanner inputFromFile = new Scanner(file);
        FileInputStream fileInput = new FileInputStream(file); // reads file
        int r;
        int y = 0;
        int i = 0;
        while ((r = fileInput.read()) != -1) { // goes through each character in
                                                // file, char by char
            char c = (char) r;
            GameOfLife.grid[i][y] = c;
            y++;
            if (y == 75) {
                y = 0;
                i++;
                if (i == 25) {
                    break;
                }
            }
        }
        // Prints the initial environment
        System.out.println("Initial set: ");
        for (int j = 0; j < GameOfLife.grid.length; j++) {
            System.out.print(GameOfLife.grid[j]);
        }
        boolean operate = true;
        while (operate = true) {
            System.out.println("Do you want to see the next generation? Y/N?");
            String q = input.nextLine();
            if (q.equalsIgnoreCase("y")) {
                GameOfLife.evolve();
                for (int j = 0; j < GameOfLife.grid.length; j++) {
                    System.out.print(GameOfLife.grid[j]);
                    operate = true;
                }
            } else {
                operate = false;
                System.exit(0);
            }
        }
    }
}

GameOfLife：

import java.util.Arrays;

public class GameOfLife {

    static final int m = 25; // number of rows
    static final int n = 75; // number of columns
    static char[][] grid = new char[m][n]; // Creates an empty (no dots or
                                            // X's)grid of rows and columns.

    static int count_neighbors(int i, int j) {
        int nn = 0; // number of neighbors of cell(i,j)

        if (i > 0 && j > 0 && grid[i - 1][j - 1] == 'X') {
            nn++;
        }
        ;
        if (i > 0 && grid[i - 1][j] == 'X') {
            nn++;
        }
        ;
        if (i > 0 && j < 72 && grid[i - 1][j + 1] == 'X') {
            nn++;
        }
        ;
        if (j > 0 && grid[i][j - 1] == 'X') {
            nn++;
        }
        ;
        if (j < 72 && grid[i][j + 1] == 'X') {
            nn++;
        }
        ;
        if (j > 0 && i < 22 && grid[i + 1][j - 1] == 'X') {
            nn++;
        }
        ;
        if (i < 22 && grid[i + 1][j] == 'X') {
            nn++;
        }
        ;
        if (i < 22 && j < 72 && grid[i + 1][j + 1] == 'X') {
            nn++;
        }

        return nn;
    }

    static void evolve() {
        for (int i = 0; i < 23; i++) {
            for (int j = 0; j < 73; j++) {
                int s = count_neighbors(i, j);
                if (s < 2) {
                    grid[i][j] = '.';
                }
                if (s == 2 || s == 3) {
                    grid[i][j] = 'X';
                }
                if (s > 3) {
                    grid[i][j] = '.';
                }
            }

        }

    }

}

Answer 1

在每个for循环后添加System.out.println()以开始在下一行打印网格。

// Print out grid.length characters
for (int j = 0; j < GameOfLife.grid.length; j++) {
    System.out.print(GameOfLife.grid[j]);
}
// Print a new line
System.out.println();

<强>更新

我上面没注意到的问题是你在一行中打印整行，并在一个（可见）循环中打印整个网格。因此，在打印整个网格后，以下System.out.println()将打印一个空白行。请参阅我的解决方案，该解决方案提取游戏的打印，对文件阅读器使用try-catch，并在底部删除不必要的operate变量，因为您还是要退出。

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.util.Scanner;

public class Project4 {

    private static void printGame() {
        for (char[] row : GameOfLife.grid) {
            for (char c : row) {
                System.out.print(c);
            }
            System.out.println();
        }
    }

    public static void main(String[] args) throws IOException {
        Scanner input = new Scanner(System.in); // Created a scanner
        System.out.println("Enter the file name you would like to use");
        File file = new File(input.nextLine()); // Takes file name to find file
        BufferedReader br = null;
        String line;
        int i = 0;

        try {
            br = new BufferedReader(new FileReader(file));
            while ((line = br.readLine()) != null) {
                for (int col = 0; col < line.length(); col++) {
                    GameOfLife.grid[i][col] = line.charAt(col);
                }
                i++;
                if (i == 25) {
                    break;
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (br != null) {
                br.close();
            }
        }

        // Prints the initial environment
        System.out.println("Initial set: ");
        printGame();

        while (true) {
            System.out.println("Do you want to see the next generation? Y/N?");
            String q = input.nextLine();
            if (q.equalsIgnoreCase("y")) {
                GameOfLife.evolve();
                printGame();
            } else {
                System.exit(0);
            }
        }
    }
}

Answer 2

我认为你应该尝试在这两个地方使用println：

System.out.println(GameOfLife.grid[j]);

System.out.print()不会自动刷新，只有在写入换行符时才会刷新。这意味着它不是写出所有内容，而是可以缓冲IO以提高效率。

2D数组不在网格中打印出来/不是完整数组？

2 个答案: